They are human. Pretty much everyone has done terrible things. If your H is forgivable/redeemable, then so are these folks.
Your father is wise to recognize that bad actions done by people in pain don't make them damnable. He is demonstrating compassion. He is also probably demonstrating hatred at his own actions by his own very flat acknowledgment of them, it is probably very hard for him right now to get any closer to his thoughts and feelings about them. I agree that his timing is poor, no doubt. But it was probably a combination of engaging in self-defense and trying to help your brother that led to him spilling the beans.
Very sorry about the tough news, it is so hard to have your world view shaken up in such ways.
