I'm going to make this quick and to the point because I can go on about this forever if I don't.

I have an online friend that's suicidal. He's nearly 5 years older than me and lives in a different state. I met him in a League of Legends ventrilo group, lost contact with him for almost a year, before he initiated contact again this October. The month before, my mum had gone all freak out and left, and they had just issued the order of protection. I still had to visit her despite that. Before long, we started talking and playing League of Legends every day. We got along well, and found we both like/watch anime. Eventually I gave him my phone number and we would text each other a lot.

One month ago, minutes after a disastrous visit with my mother that left me and my sister close to tears, my friend dropped the bomb that he'd been having suicidal thoughts. I decided to play the supporting friend and tried comforting him as much as I could, but didn't really know what to do. His demeanor towards me changed drastically after he told me. He started apologizing frequently on things he had never done, degrade himself by saying he was stupid or an ***, and asking if I was mad at him. Watching him do that every single day started taking its toll on me.

I hate seeing him do that, and have to tell him that he hasn't done anything wrong and that I'm not mad at him or want to leave him. Every single day I play with him and every single day he blames himself if I don't text back quickly enough or can't skype with him because of something I can't control like homework or being called to dinner. It hurts and I never know what to do whenever he goes into these moods and have to carefully think out anything I say to him in fear that I'll set him off. He actually jokes around every time we play League about it. What if I killed myself because you didn't heal me? or How would you feel if I killed myself because of what you did? Each time it leaves me at a loss of what to say and makes me feel incredibly guilty and sad.

Not to mention I've started having doubts about the whole thing. It seems too persistent, like it's laid on too thick, but he wouldn't lie to me about something as serious as this. He's told me on numerous occasions that he would've offed himself months ago if it weren't for me. He's asked me why I stay with him and text him as much as I do, but he doesn't understand that I can't just leave a friend for dead. Whenever he asks me why I bother, it always makes me hate myself. He trusts me out of all people with some of his problems, and here I am doubting he's telling the truth like I don't know any better.

I'm exhausted. Every day I come home from school I get 7-8 hours of watching him beat himself up and hating myself for doubting him. Then I actually have to fall asleep knowing that he probably won't sleep more than an hour or two because of his insomnia and the thoughts that plague him when he's alone in the dark. I feel like my entire life has been consumed by thoughts of my mother, thoughts of my friend, and thoughts of my quarreling sister and father.

I don't know what I'm supposed to do. I don't want to leave him, because he doesn't deserve to die and he's so much more than what he thinks he is, but telling him to back off might make him think I betrayed him and that I'll leave him and set him off. I've told him several times that watching him do that hurts, but he seems to ignore it.

Please, I could really use someone's advice.