I'm trying to write a character who completely shuts down after the death of his parents for the sake of those who were depending on him. That means he does his job, and he gets things done, but behind closed doors, there has been a major personality change. He becomes self-obsessed, angry, and controlling of his two younger sisters. My problem is that the second half of the story is about what one sister does to try to save what's left of his good side after the other sister runs away. I don't want to do anything that comes close to saying that abusive relationships are okay, or give the impression that they'll change if you just stick it out. So how can I write the character so that he is bad enough that it warrants fairly drastic action on his sister's part, but not bad enough that their situation could be seen as abusive?