Youth don’t magically become more responsible or “adult” the day they turn 18. It’s a legal designation. That 17 year old is as “adult” now as he will be within next several months when he turns 18.
I doubt you’ve ever been on the receiving end of an ass whupping. It has an amazing effect on behavior correction. Daddy won’t go to jail over this and his daughter isn’t going to hate him for it and run away.
I’m betting there are countless women out there and even on this board who wish their dad had fought for them when they were doing stupid stuff in their teens.
My older sister left home at 17 and never returned. I did the same.
Daughters do appreciate it when their parents protect them, when they let them know that they are priceless and worthy of protection. You do this from the cradle, so they don't feel a need to find affection in the arms of a male at 15.
Daughters also like to feel safe. When dad's finished taking his anger out on boyfriend, will she be next? If dad can't control his temper in public, will he in private?