Okay, see, I have an issue here. The issue is more or less that on the one hand, I feel like I ought to advise seeking professional help and talking through this by demonstrating concern for his emotions and feelings... or, on the flip side, just kicking his butt to the curb. On the other hand, I wouldn't actually handle it that way, and I don't think many people here would, either. So giving advice that only works if you've got the patience of Buddha strikes me as somewhat less than helpful.
"Dude, this guy keeps kicking me in the shins. What should I do?"
"Transcend your earthly limitiations. Become more than just a body that has shins that are being kicked."
So, my advice, honestly, is to give the dude what he wants -- attention -- but to also call him on it.
"Look, we like you, we care about you, but if you're going to run off and pout every time somebody says something that you don't personally agree with, you're going to have a long and unpleasant life. As you've told me once or twice in your ten-page personally hurt e-mails, you've had a very hard life. That's swell. It's going to continue to be hard and unpleasant and full of chances for you to be victimized by harsh uncaring people until you pull your head out of your back pocket and actually learn to communicate with peoplle on some level other than 'You hurt my feelings, can't you see how deeply that wounds me?'
"We don't want to kick you out. We don't want to hurt your feelings. However, we're also not your therapists. Unless you want to pay us all $50 per hour to let you act rude and childish to us, you need to figure out a way to get your attitude under control. If you'd like to talk about it with one or all of us in a constructive way, we'd love to hear from you. We're your friends.
"But again. We're not your therapists. You are victimizing us with your behavior. You are making us feel the way you claim to feel every time you storm off in a pout and send us wounded ten-page e-mails. If life is unpleasant and you need someplace to come relax with people who aren't going to judge you or mock you unfairly or cast you out because of who you are, we can be your buddies and your haven. But acting spoiled and rude on a consistent basis will result in a loss of priveleges."