Worried about this child rubbing off on my son

My son joined robotics this semester and made some friends. One we will call A. A is obnoxious and says gross sexist stuff. When a girl joined robotics A was over here telling my son. How he can't wait to see how long it takes her to cry and quit because girls are too emotional for robotics. Then talks about how he's definitely going fuck her and stuff like that. He's 15. He was over yesterday and his step dad died. I offered my condolences and he said it doesn't matter. My son asked would he rather be home with his sisters and mom because his step dad is his sisters' biological dad. He says "God no. I can't stand crying women. No man wants to listen to bitches wail all day you know what I mean?" My son told him he doesn't understand what he means 90 percent of the time. I just don't like this child and I feel he can become a very bad influence very quick.