What is the main conflict in The Lost Boy by Dave Pelzer?

David Pelzer is a child taken into the foster care system at age twelve, though he had spent years being tortured and tormented by his mother. David is one of five sons and there's no real indication why he was singled out for his mother's attention. David's father is present during his early years, though he wants peace in his household at any cost—even if it means David is being beaten and tormented.