What should I do about my friend being a jerk?

Friday, my friend was saying I should kill myself and that my accomplishments with my cutting weren’t good enough. I have gone 2 and a ½ months without cutting when i was doing it every day at one point. I feel hurt by what he said. Then I help out with people at my school who have disabilities and he started to make fun of them. I felt very offended. My mom thinks he is fine even though he has been doing this for almost a year and is really starting to hurt my feelings. I don’t know what to do because he said if i stop being his friend he will kill himself and it will be all my fault. But I don’t want to get hurt anymore and I don’t want him to kill himself and it be on me.