I think the next couple of chapters will do a better job of spelling out Brad's motives, but that really isn't the big issue here. The big issue is that Will is feeling pretty isolated, and as I said in one of the reviews, when a 14 year old guy like Will is feeling embattled, his reaction is going to be to lash out. The stronger he fights, the more upset he is. There's an imbalance in his life, and he's trying to get his father to notice him. Brad, in his defense, is trying to balance a bunch of different things as well. Until they figure out how to find a harmonious convergence, it's not going to go very well.