How do I talk to my friend?

So me and my friend just moved in together. She started seeing this guy but he lives in a hotel and I work with him. Ive heard he’s so far broken in a car and he just popped out of nowhere. I live in a small town and everyone knows everyone. And nobody knows him. Well she started talking to him, she was happy. But every night they get in a fight and he says hurtful words to her. Then she comes home to me crying. Then in the middle of the night she’ll go knock on his door to apologize. Then last night she brought him over for the first time and it seemed to be going good and I leave for a little and come back and he’s gone and she is crying. He got mad at her again. Now this morning is all good...I keep telling her relationship don’t work this way. But she keeps going back. I don’t know what to do.