What would you do about this?

Okay so my friend is dating this guy for the 6th time and each time they broke up it was because he wanted to F her sister or he was texting some other chick and now shes sad because he has a bunch of pictures of naked girls on his phone. Shes calling me pissed idk what to tell her other than to dump him and never come back but "she loves him" What would you say i feel bad just sitting here silent on the phone while she vents.