A friendship is mutual. If it is one-sided, that is not friendship. Just cut them off and move on. You will both benefit as you find someone who appreciates you and they stop being miserable all the time.
Then he or she is not your friend.
friends don't treat each other like that, don't let him/ her being rude or mistreating you. Stay away from that kind of person...If you've already tried to talk and the person still insists on this type of attitude and they're not just stupid and don't see what they were doing to others, then yes, I think the right thing to do is to cut off this type of friendship.