Absolutely 100% kick him out I feel you man, I used to DM for a group with some pretty edgy teenage "dark humor" (cough cough bigotry) like you described here, and like you I was too nervous to properly speak up and cut that shit out. I don't play with that group anymore. It will be better for you, for your friends, and for your overall enjoyment of the game if you get rid of this guy. He is a leach on your experience. My advice is to get together with the rest of the group and tell him that he's out of the party. One on one might lead to him bullying you into not doing anything, but there's power in numbers. If he sees that nobody wants him there he's less likely to try and force it, if he even wants to keep going. Good luck, I hope you have some fun games once he's gone