Joey Pigza has ADHD or something equivalent to that. He is frustrated because he can't seem to keep himself from getting into trouble. His parents give up on him and abandon him at his grandmother's home. She resents having been saddled with him and is openly hostile. Growing up Joey is constantly in trouble. They finally put him on medication and it seems to work, sometimes. Then, when his mother comes back into his life, everything is thrown out of whack again.
Enter Ed Vanness. When he mets Ed Joey begins to have hope that there is a way to cope and live with his condition. Mr. Vanness also helps him admit that many of his problems stem from his earlier childhood and his relationship with his estranged parents. Later, when he is able to confront his mother Joey begins to see her as a huma being who is struggling with her own sets of problems. This allows him to eventually let go of his past, go on new medication and to find the type of friends and support structures that allow him to live the life that the thought he'd never be able to have.