Boyfriends friend a creep??

So awhile back my boyfriend and I got drunk with his friends. I got too drunk and was laying on the couch / falling asleep, then randomly I felt someone touching me trying to put their hand down my pants??? It turned out to be his friend. Obviously I was pissed and now I do feel very uncomfortable around said friend and no longer drink around him. Would it be okay to ask my boyfriend to distance himself from the friend? His friend wants us to come to his diaper party and I don’t think I feel comfortable. Especially because this friend gets petty and mad at him when he tells me he loves me / starts saying things that aren’t true to me and blames it on being drunk and never getting to spend time with my boyfriend. I am unsure on what to do because they’ve been friends since they were children and their families are friends and don’t want to overstep anything