My 16 year old son frequently punches his 18 year old sister, just in the arms, in a supposedly playful manner, but he is bigger than her, it hurts her and he seems to think it's fun, acceptable behaviour. She will sometimes push or hit him when he is mean to her, it has to be said, which I strongly object to, and this is not happening very often. However, most of the time it is my son who is being physical. He is not like this with anyone else, and is well behaved at school etc. Also, he is very critical of her a lot of the time, calling her annoying or stupid etc, and barely being able to stand her speaking or being around him, especially if he is playing on the play station. Still, he is happy to get her help with questions concerning his GCSE revision, and has plenty time for her then. And just recently, since talking to her in this regard has improved somewhat in the general respect he shows her, because before that it was pretty much non- existent to the point that she thought she could never be friends with him when they are all grown up.
I feel he should not be hitting her, as he is bigger and stronger. And aside from the fact he should not be hitting anyone, I think he especially should not be hitting a girl, even his sister. I tell him this, and get upset at his behaviour, but he doesn't stop, and finds me annoying. I think his father, as a male role model, should be the one to make it clear that this behaviour is unacceptable, but I'm not sure he does this enough, he definitely does not object to it as strongly as I do. Also, he hasn't managed to make it stop, and he makes excuses, like he's just playing, it's what boys, but why should he feel entitled to hurt is his sister in this way, albeit in a playful manner. My son has more respect for his dad than he does for me, and as his father, he is a strong male role model, so shouldn't it be his job to tell his son it is not ok to hit girls.