Halley's genuine devastation when she realizes that CPS knows that she's prostituting herself and she's going to lose custody of Moonee.
The final scene in which Moonee, a child who's been cheerful in the face of nearly everything that's happened to her so far, runs to her best friend's room and breaks down in tears. It's a heartbreakingly realistic performance from such a young child actor.
The scene where Ashley realizes that Scooty burned down the nearby abandoned house and tries to get her son to realize just how much trouble they could get into if anyone ever found out.
After this, Ashley forbids Scooty from playing with Moonee and Jancey, leaving him perpetually confused and sad at being forced away from his friends.
It's not heavily emphasized, but any scene between Bobby and his son shows their relationship slowly deteriorating.
