This girl has family, right?
I would contact a close member of her family, -perhaps mother or father,... and explain to them what is happening.
Have them bring a domestic violence order against this creep before things get worse. At the very least, by doing this, HE should get a visit from the authorities.
Mental torment is STILL domestic violence, and can be just as damaging as physical violence. Sorry, but as her good friend YOU are obligated to step in and do something, before the inevitable happens.
My own sister was in a very abusive marriage, which she kept quiet about for a number of years. There were children involved, so
she could not "see" a way out. For the sake of the kids she stayed with this pig for many years, suffering physical and mental torture.
When I finally found out what this guy was doing to my sister... (at the time of my intervention he had beaten her so badly, she was in hospital for ten days) I went to her, and took full colour photographs of her battered and bruised head and body. I then got the address details of every one of their friends, and especially HIS family. Every single one of those people in her address book received a letter and photographs explaining what he had done to her, over the period they were married.
Let me finish by saying that this maggot unfortunately still lives, but he has been disowned by his family and has no friends. My sister also sued him for every penny she could get, and he is now a bankrupt.
I am not a violent man myself, but I will say that I also paid him a visit -and left him with a warning I'm sure he will remember to his grave. He has not been near my sister since that day.
Spyderbyte......
Intervene! Do it for her, and do it for your own peace of mind. Do your utmost to get her out of there.
Please!