From your post it seems that you think that a child hurt him before he came into your home? I have known a few pits from a rescue I used to help with who had issues with certain individuals. For example, one hated males and could only be around females. He would feel very threatened by males and would growl and lunge at them. It was caused by his previous abuse.
May I ask where you got him from? That may explain his behavior. I would be worried though about him not being comfortable around children. I wouldn’t want that risk.