How to deal with or get rid of feelings for someone

Ok so a little bit of backstory I have this friend who I'm rly close with and maybe around two months ago I started hanging out with him and his friends at school. After this i started liking his best friend, noah, and I mean i RLY liked him. Me and him eventually started talking but he's not interested in me at all actually he's not interested in anyone at all. He struggles alot with his self esteem and mental health and stuff but whenever his friends or family try to help him he pushes them away. He's a really shit friend in general to alot of people. Every time some girl likes him he thinks he's not deserving of her and how he's the worst person alive and how he deserves everything bad that has happened to him. I think cuz of that he rly feels that no one truly likes him maybe. I try to help as a friend but he rly js pushes me away and always just keeps his worries and thoughts to himself. And this makes him lash out on people and he's also a bit self centered so basically he's a very shit friend. In the end of the day I still really really like him I have no idea why since he's such a terrible person (there are alot more reasons that make him a terrible person but I'm js too lazy to write them) but I still really like him I have no idea what to do anymore cuz I can't seem to get rid of these feelings. Any advice?