Natasha explains that she and Samuel used to be inseparably close. They were the dreamers, while Patricia and Peter were the "non-dreamers." Natasha listened to her dad talk long after her mom and Peter stopped listening, but that changed when Natasha was thirteen. Patricia was tired of living in a one-bedroom apartment and making so little money. She often lamented her fate to Natasha.
Though it's important to keep in mind that Natasha viewed her parents' relationship through the lens of being a child, it's clear that Patricia was becoming and feeling more and more isolated in her marriage. Her association with Peter suggests that he's also still feeling isolated.
Then, Samuel lost his job. He said that maybe it was a blessing that would allow him to pursue acting, but he seldom auditioned. One afternoon, Peter and Natasha arrived home from school to find him in the living room, reciting lines from A Raisin in the Sun. Samuel was holding the script, even though he had it memorized. He was reciting a monologue about seeing his future stretched out, empty, in front of him. When he noticed his children, he seemed ashamed that they'd caught him, and he scolded them.
The monologue that Samuel mentions allows the reader to gain a greater degree of insight into Samuel's thoughts: he appears to actually see his future as empty and devoid of meaning. When he scolds his children, it suggests that he meant this moment to be a private one, which shows that he's drawing into himself and no longer allowing others to witness his true thoughts.
After that, Natasha and Samuel didn't do things together anymore. He began spending all his time in the bedroom, reading and reciting long and dramatic monologues. Patricia took extra shifts to make ends meet, and Natasha began working during the summers. Two months ago, Samuel managed to get a part in a small production of A Raisin in the Sun. When he told Patricia, she asked him flatly how much he was getting paid. Everyone was shocked that she reacted this way, but Natasha suggests that her mom wasn't at fault—her dad spent years living in plays instead of the real world, and neither Patricia nor Natasha have time to dream anymore.
Notice that Natasha gave up on passion and dreaming not because of something that happened directly to her, but because of something that happened to her father—someone she used to be close to. This reinforces the idea, though Natasha doesn't seem to realize, that she is actually intrinsically connected to others, given that someone else's experience can bring about this shift in her.