She needs to change the locks or move, this isn't going to get better only worse, I don't mean to scare you but if he is that violent then there isn't anything he will not do, he could hurt your b/f his daughter or really hurt his exwife, she & he need help...I am speaking from experience it doesn't get better....tell your b/f sister in a nice way to wake up and do something, people don't change....
