Tell her to go to 1) the police. This is assault (domestic assualt at that, even if it is just a roommate), and the guy should be dealt with accordingly. And 2) her present landlord. There is no reason for her to move, and every reason for this prick to be thrown off his lease. If the landlord doesn't act, she has legal grounds against him. Then give her the number to your local domestic abuse hotline. She should take advantage to every resource afforded to her, she'll need it.