Please help my friend

Right now I'm talking to one of my friends and he wants to kill himself. Im trying to talk him out of it but he keeps saying that he has nothing to live for. He's bi-polar and attempted suicide before and if the door didnt accidently open he would be dead right now but that was before we were friends. He's one of my best friends and sometimes I feel like he's the only person who understand me and I don't want to lose him. A few days ago he told me he liked me but I don't feel the same way so I told him we can just stay friends, Im sure he'll find a girl who loves him but that girl isnt me, he saying its not about me its about something else but I feel like such a bitch now. He says his life is shit and he has nothing to live for but I believe in him and I keep telling him that things do get better. He's always been there for me so please help me be there for him. He's not a big MCR fan, he only knows two songs but please Killjoys help me, I don't know what to do and I don't want to lose him.