Hermione reads a Daily Prophet article—in which Fudge admits that Voldemort is back—to Harry, Ron, Luna, Ginny, and Neville from her bed in the hospital wing. Ron still has welts on his arms from the brain’s attack, and Hermione is still in pain from the Death Eater’s curse. Hermione notices that the Prophet is also running the interview Harry gave to The Quibbler, and Luna says her father sold it to them. They're using the money to go to Sweden to look for Crumple-Horned Snorkacks. Hermione is able to say that it sounds like a lovely vacation. They all discuss that Flitwick got rid of Fred and George's swamp and everything has settled down.
The fact that Hermione can act supportive of Luna's vacation to look for creatures that don't exist shows that Hermione has learned something about respecting others and not belittling those she thinks are wrong. Flitwick is an accomplished wizard who could have gotten rid of the swamp the whole time, but he clearly chose to let it remain as both an homage to Fred and George and a hindrance for Umbridge.
They look over and see Umbridge in her bed. Dumbledore saved her from the centaurs, and she hasn't spoken since she came out of the forest. Ron imitates the sound of hooves, which makes her sit suddenly upright, terrified. As Hermione and Ron squabble about the existence of real prophecies, Harry nervously excuses himself to go see Hagrid. He hasn't shared what he learned in the prophecy.
At this point, keeping what he learned about the prophecy a secret allows Harry to come to some conclusions in regard to how he feels before inviting other opinions. It's a choice to keep this a secret, so it feels powerful for Harry and doesn't destabilize him.
Harry can't decide if he wants to be around people or not. As he enters the entrance hall, he sees Crabbe, Goyle, and Malfoy. Malfoy threatens Harry, since Harry put Lucius in Azkaban, and Harry pulls out his wand. Snape breaks up the fight and tries to take points from Gryffindor, but there aren't any points left to take away. Just then, McGonagall arrives and awards Harry and his friends 50 points each for alerting the world about Voldemort, and then takes ten from Gryffindor for Snape.
Now that Umbridge is no longer in charge at Hogwarts, McGonagall can show Harry how she really feels about all he's done this year by awarding him points for telling the truth. Though this is a small thing, it allows her to thank Harry, show him her support, and reinforce that it's important and valuable to tell the truth, even when doing so is difficult.
Harry and Hagrid have an awkward cup of dandelion juice. Hagrid tries to say that Sirius would've wanted to die in battle, but this cause Harry to excuse himself. He walks around the lake, thinking that he feels isolated from everyone since speaking with Dumbledore. Harry thinks that he's not afraid, but it feels hard to believe that he'll either murder someone or be murdered.
Harry is grieving, and not speaking about Sirius is how he feels most comfortable. Again, this shows that when Harry is control of whether or not he doesn't talk about things, it can be a healing and empowering thing. The prophecy makes Harry feel cut off from his peers, and even doomed in a sense, which is exactly why Dumbledore kept this information from him for so long—he was trying to protect him.
Ron and Hermione get out of the hospital three days before the end of term. Umbridge leaves the school two days later, chased by Peeves when she finally exits. Harry considers skipping the end-of-term feast to pack and avoid the crowd. He finds a package at the bottom of his trunk and realizes it's the gift Sirius gave him after Christmas. It's a small mirror, and the note says that Harry can use it to speak to Sirius. His heart racing, Harry says Sirius's name to the mirror. Nothing happens. He throws it into his trunk and it shatters.
Shattering the mirror symbolically represents how shattered Harry feels after losing Sirius—he feels disconnected from anyone and can't speak to people, just as he cannot speak to Sirius. This is also likely very difficult for Harry, as now that he knows what the gift was, he could've used it to check more effectively if Sirius was home after his dream.
Harry realizes he has one more possible way to talk to Sirius. He races down to the entrance hall and finds Nearly Headless Nick. Nick seems to have been expecting Harry and acts uncomfortable. Nick says that students often come to him after losing someone. When Harry asks, he says that not everyone can come back as a ghost. He continues that Sirius will have "gone on."
Though Nick's explanation feels unsatisfactory to Harry, it's important to recognize that after his ordeal, Harry is now more willing to ask for help. This shows that he's beginning to take what he learned to heart and can now look to his wider community to help him make sense of confusing things.
Harry wanders through the castle until he runs into Luna at a notice board. She greets him serenely and says that she's putting up flyers, as people think it's funny to hide her things and she needs them back now. Harry feels sorry for Luna and offers to help, but she refuses with a smile. They discuss Sirius and Luna says that she can see thestrals because she saw her mother die. She says that she'll see her mother again, and reminds Harry of the voices they heard behind the veil in the Department of Mysteries.
It's telling that it's only now, in the final pages of the book, that Harry takes a genuine interest in Luna and who she is as a person. This suggests that because Harry is now in a more mature place, he's able to look for others outside of his usual circle. The book continues its exploration of the nature of death, as Luna seems to confirm that the whispers beyond the veil were those that have died. She suggests that Sirius won’t really be gone, and this vague conversation is more comforting to Harry than any other he has had since Sirius died.
On the train the next day, Malfoy, Crabbe, and Goyle try to curse Harry, but most of the D.A. comes to Harry's defense. Later, Cho and Marietta, who's wearing a balaclava, walk past the compartment, looking embarrassed. Hermione hesitantly says that Cho is dating Michael Corner, and Harry finds he doesn't care. Ron asks Ginny if she's not dating Michael anymore, and Ginny says she's now dating Dean Thomas.
When everyone in the D.A. curses Malfoy, Crabbe, and Goyle, it reminds Harry that he now has friends throughout the school to help him when he needs it. With this, Harry is able to take the Sorting Hat's warning to heart and recognize that Hufflepuffs and Ravenclaws will be there for him, despite their differences. Harry also once again decisively chooses his friends over his romantic interest in Cho.
When the train arrives in King's Cross, Ron, Harry, and Hermione step through the barrier and find an unexpected welcoming committee composed of Moody, Tonks, Lupin, Mr. Weasley, Mrs. Weasley, Fred, and George. The group approaches Vernon and Petunia, who are also there, to tell them that there will be consequences if they discover that Harry is being mistreated. To make his point, Moody lifts up the hat covering his magical eye, shocking Vernon. Harry follows Vernon out of the station.
With Sirius gone, it now falls to the entirety of the Order of the Phoenix to advocate for Harry to the Dursleys. This again reminds Harry that even as he loses people he loves, his community will continue to expand. He has lost one of his closest friends and mentors, but he no longer feels so isolated from the other adults in his life.