Question for your teenage self?

My 18 year old daughter is dating a guy that everyone in our family thinks is an absolute wrong choice for her. Not just immediate family - I'm talking aunts, uncles, grandparents and her friends too.

He speaks down to her, uses and goes through her 'phone, says really bitchy things and then claims it's a 'joke' and (in my opinion) bullies her by being passive aggressive and sulky.

She was recently hospitalised with severe abdominal pain and he thought it would be fun to poke her belly to 'test' if the morphine and oxycodone was working yet - yes! the pain was that bad ): They broke up yesterday after he objected to being told how unsupportive he had been while she was ill but he now seems to have convinced her to give him another shot. They had a screaming fight and he damaged our front door through slamming and/or hitting it but now it is all supposed to be fine :(

We have tried to be as supportive of her as we can but I think the horrendous peer bullying that she has been through has left her vulnerable to this type of control. My major concern is that through his controlling and manipulative behaviour he is alienating her from her support network (both friends and family). My friends that I have seen date men who exhibited these behaviours have ended up in very abusive relationships.

Please, can anyone give me some advice on how to help her to see that she deserves better than this?