Really clingy online friend who gets suicidal if we don't talk to him. Help?

I have an online friend who is super clingy. He is disabled and unemployed so all he does is talk to his friends (us, a small group) all day. We were getting frustrated with him because he wasn't taking our advice about improving his life, instead he just gets depressed and resorts back to the same bad habits. He seems addicted to talking to us. I felt like I was enabling him so I stopped talking to him so much, but he still does things like send us emails almost every day, write me letters and snail mails them. That's all well and good, but he's unemployed and needs to work on his skills/job applications/school applications/life improvements instead of devoting all his energy to that.

Anyway, he was starting to get on my nerves for other reasons which helped to push me toward ending contact, and now he's moping and threatening suicide. I really can't deal with this anymore. I'm not his girlfriend! I hate to say it but I just don't want to be his friend, and it feels like a burden. We're not even that close, he just thinks we are because we've talked online. I don't know what to do because I also feel guilty.

tl;dr see the title.