Age gap... do I confront my friend?

Sami
So I might be stuck in my own ways, but personally I feel like when older men go after teenagers it's nothing but a creepy physical thing... I'm not for it. But my best friend is 19 and she's currently "with" a 32 year old and He's seeing other women and it's like she's blind. He treats her horribly, refuses to give her a relationship title, and tells her what to do, and when to come over for sex. And he's even told her that he wants to have a threesome with me and her and I've never even met him and it disgusts me! And frankly it gives me chills just thinking about how he is taking advantage of my friend. My friend and I are moving in together in 3 months and I know she's going to want to have him over... And I do not want him in my house... Do I suck it up? Or do I tell her he isn't allowed in my house?