More so than any of the previous installments of the Harry Potter series, Harry Potter and the Deathly Hallows is intensely focused on death, especially in terms of how the living coexist with and make sense of their memories of the dead. For Harry, who is still reeling after the death of Dumbledore at the end of the series' previous installment, coming to terms with who Dumbledore was in life is Harry's final step to maturity and into the adult world. In this way, while the novel makes it clear that coming to terms with a deceased loved one's legacy is a difficult proposition for everyone, it's particularly difficult and transformative for young people.
Harry's struggle to comprehend Dumbledore's death and to fully accept it is compounded by the fact that, at several points throughout the novel, Harry believes he sees Dumbledore's piercing blue eye looking at him through a two-way mirror fragment given to him by Sirius. To Harry (and, at points, to Ron as well), this suggests that maybe Dumbledore isn't actually dead—something that, within the logic of a magical world in which many unthinkable things are possible, isn't entirely illogical. Though Harry does seem to understand on some level that Dumbledore is truly dead, this issue of acceptance is magnified again when Harry learns about the Deathly Hallows and, specifically, about the Resurrection Stone—which purportedly has the power to bring people back from the dead, albeit in a form that's not fully human. Of the three Hallows, this is the object that Harry covets the most: the number of people close to him that he's lost and the amount of grief that he's experienced in seventeen years of life means that he often finds himself longing for the company of the deceased. For Harry, then, much of his coming of age over the course of the novel happens as he gradually learns that the dead should indeed stay dead, and that dwelling on the dead inevitably leads to forgetting or neglecting the business of living.
Harry begins to make these leaps as he sees increasingly that seeking out the dead isn't actually guaranteed to give him a sense of companionship and belonging, something that he's spent his life craving after being orphaned as a toddler. More alone in the world than ever, Harry spends the first several months of his, Ron, and Hermione's journey fixated on visiting Godric's Hollow, where Harry was born and where his parents are buried—and, as it turns out, where Dumbledore's family also lived. Though Harry expects to discover a sense that he belongs in Godric's Hollow, or simply to find answers about his family or about Dumbledore, his experience there is more unfulfilling than not. Finding his parents' graves is meaningful and emotional, but one of the only things of note that Harry and Hermione pick up there is a copy of Rita Skeeter's sensationalist biography of Dumbledore.
Harry, who has been dealing with Rita Skeeter's questionable reporting for years at this point, understands that he can't take everything she writes as fact, especially when her subject is someone like Dumbledore, with whom she openly butted heads. However, Skeeter's reporting, combined with Harry’s growing doubts and questions about Dumbledore, make Harry feel even more insecure about his relationship with his former headmaster. In the six years that Harry knew Dumbledore, Dumbledore never shared that they had this shared connection to Godric's Hollow and, therefore, never confirmed or denied any of the allegations of what happened there—which in turn, leaves Harry unsure of what to believe and whether he should still believe in Dumbledore's mission.
Dobby's tragic and untimely death begins to put in perspective for Harry that the dead can only provide so many answers. Harry sees the blue eye in the mirror before Dobby arrives (and therefore concludes that Dumbledore somehow must have sent Dobby), and he chooses to read this as proof that Dumbledore knew what he was doing and did care for Harry—even though there's no proof that Dumbledore was behind it and, indeed, even though Harry discovers that Dumbledore's brother Aberforth actually sent Dobby. This represents a major transformation in the way that Harry thinks about his relationships to the dead. By choosing to reapply himself to his quest and, by extension, to all of the good things that Dumbledore stood for, Harry effectively begins to control how he interprets the narrative of Dumbledore's life. Put another way, Harry stops fixating on Dumbledore the person and instead focuses on how he can best honor Dumbledore's memory through his actions.
However, this doesn't mean that Harry doesn't still crave a final conversation with Dumbledore, hence Harry's imagined conversation with his headmaster while Harry is effectively dead. It's important that the Dumbledore Harry speaks to is a creation of Harry's mind, not a return of the man himself. In this dreamlike state, Harry is able to orchestrate a final advice-giving conversation with his mentor—though again, all that he learns are things that he subconsciously knew, but needed the nudge of a mentor to fully grasp. Through Harry's conversation with this Dumbledore, Harry is able to come to terms with Dumbledore's legacy, while his choice to return to the land of the living signifies his final shift from child to adult—and his choice to continue to fight for the positive aspects of Dumbledore's legacy. That Harry, almost two decades in the future, endeavors to impart wisdom that Dumbledore once gave him to his son suggests that the best way to honor a person's legacy is by doing exactly this.
Grief and Coming of Age ThemeTracker
Grief and Coming of Age Quotes in Harry Potter and the Deathly Hallows
He had thought he knew Dumbledore quite well, but ever since reading this obituary he had been forced to recognize that he had barely known him at all. Never once had he imagined Dumbledore's childhood or youth; it was as though he had sprung into being as Harry had known him, venerable and silver-haired and old. The idea of a teenage Dumbledore was simply odd, like trying to imagine a stupid Hermione or a friendly Blast-Ended Skrewt.
Dumbledore would have believed him, he knew it. Dumbledore would have known how and why Harry's wand had acted independently, because Dumbledore always had the answers; he had known about wands, had explained to Harry the strange connection that existed between his wand and Voldemort's...But Dumbledore, like Mad-Eye, like Sirius, like his parents, like his poor owl, all were gone where Harry could never talk to them again.
"It's traditional to give a wizard a watch when he comes of age," said Mrs. Weasley, watching him anxiously from beside the cooker. "I'm afraid that one isn't new like Ron's, it was actually my brother Fabian's and he wasn't terribly careful with his possessions, it's a bit dented on the back, but—"
Harry looked into Doge's earnest, pained face and felt, not reassured, but frustrated. Did Doge really think it was that easy, that Harry could simply choose not to believe? Didn't Doge understand Harry's need to be sure, to know everything?
The accusations he had heard from Muriel at the wedding seemed to have nested in his brain like diseased things, infecting his memories of the wizard he had idolized. Could Dumbledore have let such things happen? Had he been like Dudley, content to watch neglect and abuse as long as it did not affect him? Could he have turned his back on a sister who was being imprisoned and hidden?
"Sirius was horrible to Kreacher, Harry, and it's no good looking like that, you know it's true. Kreacher had been alone for a long time when Sirius came to live here, and he was probably starving for a bit of affection. I'm sure 'Miss Cissy' and 'Miss Bella' were perfectly lovely to Kreacher when he turned up, so he did them a favor and told them everything they wanted to know. I've said all along that wizards would pay for how they treat house-elves. Well, Voldemort did...and so did Sirius."
The rain was pounding the tent, tears were pouring down Hermione's face, and the excitement of a few minutes before had vanished as if it had never been, a short-lived firework that had flared and died, leaving everything dark, wet, and cold. The sword of Gryffindor was hidden they knew not where, and they were three teenagers in a tent whose only achievement was not, yet, to be dead.
Indeed, as Phineas Nigellus talked about Snape's crackdown, Harry experienced a split second of madness when he imagined simply going back to school to join the destabilization of Snape's regime: being fed, and having a soft bed, and other people being in charge, seemed the most wonderful prospect in the world at that moment.
"'The last enemy that shall be destroyed is death'..." A horrible thought came to him, and with it a kind of panic. "Isn't that a Death Eater idea? Why is that there?"
"It doesn't mean defeating death in the way the Death Eaters mean it, Harry," said Hermione, her voice gentle. "It means...you know...living beyond death. Living after death."
Dumbledore had left them to grope in the darkness, to wrestle with unknown and undreamed-of terrors, alone and unaided: nothing was explained, nothing was given freely, they had no sword, and now, Harry had no wand. And he had dropped the photograph of the thief, and it would surely be easy now for Voldemort to find out who he was...Voldemort had all the information now...
He was not being kind or generous. As certainly as he had known that the doe was benign, he knew that Ron had to be the one to wield the sword. Dumbledore had at least taught Harry something about certain kinds of magic, of the incalculable power of certain acts.
Ron looked a little embarrassed, but said in a low voice, "Dumbledore...the doe? I mean," Ron was watching Harry out of the corners of his eyes, "he had the real sword last, didn't he?"
Harry did not laugh at Ron, because he understood too well the longing behind the question. The idea that Dumbledore had managed to come back to them, that he was watching over them, would have been inexpressibly comforting. He shook his head.
"Sometimes I've thought, when I've been a bit hacked off, he was having a laugh or—or he just wanted to make it more difficult. But I don't think so, not anymore. He knew what he was doing when he gave me the Deluminator, didn't he?" He—well, [...] he must've known I'd run out on you."
"No," Harry corrected him. "He must've known you'd always want to come back."
He did not want to express the doubts and uncertainties about Dumbledore that had riddled him for months now. He had made his choice while he dug Dobby's grave, he had decided to continue along the winding, dangerous path indicated for him by Albus Dumbledore, to accept that he had not been told everything that he wanted to know, but simply to trust. He had no desire to doubt again; he did not want to hear anything that would deflect him from his purpose.
Dumbledore had warned him against telling anyone but Ron and Hermione about the Horcruxes. Secrets and lies, that's how we grew up, and Albus...he was a natural...Was he turning into Dumbledore, keeping his secrets clutched to his chest, afraid to trust? But Dumbledore had trusted Snape, and where had that led? To murder at the top of the highest tower...
"All right," he said quietly to the other two.
And Dumbledore had known that Harry would not duck out, that he would keep going to the end, even though it was his end, because he had taken trouble to get to know him, hadn't he? Dumbledore knew, as Voldemort knew, that Harry would not let anyone else die for him now that he had discovered it was in his power to stop it.
"Tell me one last thing," said Harry. "Is this real? Or has this been happening inside my head?"
Dumbledore beamed at him, and his voice sounded loud and strong in Harry's ears even though the bright mist was descending again, obscuring his figure.
"Of course it is happening inside your head, Harry, but why on earth should that mean that it is not real?"