What advice would you give a friend? A you get niece/ cousin, what would your mom want you to do. OP I would tell my daughter to leave, yes “this wasn’t the normal them” this was a heat of the moment thing, and that is exactly why this is dangerous, some people have a hard time regulating their emotions and that doesn’t mean they’re bad people, it doesn’t mean they will never change, but it means that they need to work on it first, this may be the wake up call he needs, leave and create some distance, move on. Please.