What would you say to a guy who takes innocent girls virginity by seducing them in?

I have a friend who is so in love with this Co worker who is a womanizer. He's good looking and have that soothing nice personality when it's all FAKE. One time I saw him talking to his pals and I hid because I heard they mention my best friend (she's like a sister) he said he so far touch up on her, and that he knows how to talk to girl and make them fall for his trap and how he manages to get a whole lot of girls(it's true) My friend knows this but still wants him. He has been feeling up on my friend and she said that she won't give up her virginity and etc s to not worry. She even said that she thinks he's falling for her. I' thinking about confronting him or even seduce him and lower his EGO! if you only knew!!!