I think Cooper was making the wrong decision not to talk. He was not one hundred percent sure that the stepdad abused him or if he would abuse him in the future. The best thing he should have done is tell the police and make sure the abuse doesn't happen. He should have told Lynn that he is willing to give up Evan if she makes sure he is safe. In his condition, Evan shouldn't be living in a car. If his father can prove that he was able to take care of him and that Lynn's new husband is abusive, he should get custody. He is almost breaking his vow of do no harm by putting Evan in a place where he has to live on the streets.