Jess - What a weirdo!
First of all, You are one of the least flaky, self-absorbed, or lazy people I know! If he wants to blame you for his problems, he's not going to get very far.
Second of all, I don't know what his prescription is, but unless it's some kind of barbituate he's developed a dependence on, quitting cold turkey is NOT fatal. Withdrawal symptoms suck (I take a prescription medication every day, and I get unpleasant symptoms if I skip a couple of days - but it's more to do with feeling crappy than about to die). Unless he has epilepsy or something, I don't know.
You're right - it's totally NOT worth it, and I can't believe he would treat you like that. He sounds like the kind of guy who was hanging around in case you became "useful" for him. Since you didn't offer sex or enable him to get drugs, then what's the point of having you as a friend?
Furthermore, this whole thing with him blocking you and not wanting to talk to you - this is a mind game. I've seen it a million times, and I guarantee you that he WILL try to talk to you again. Right now, he's "punishing" you for not eing agt his beck and call. He's hoping you'll learn your lesson, and feel lost without him as your friend.
My freshman year roommate in college was the same way - I know it when I see it. She'd "punish" me by giving me the silent treatment for not paying enough attention to her, not smoking pot like she did, and not having sex with anyone other than my boyfriend. Little did she know that it was a great form of punishment for me - she never stopped talking about herself and it was such a relief when she put on the silent treatment. I could finally hear myself THINK. She'd panic and try to get all "nice-nice" with me when I started hanging out with the person who soon became (and still is - her name is also Jess, incidentally) my best friend.
The best way to deal with this crap he's giving you is NOT to play back. And I think you're doing a good job so far of not playing back as it is. It doesn't sound like you really need him in your life, anyway. From what you've said in this post, he doesn't bring that much to the table except amusing ramblings from time to time.
I'm angry on your behalf, too! There are very few things in this world that legitmately ANGER me to the point where I'm all ready to fit the redhead stereotype. Immaturity and rudeness are the main ones, because there's no excuse for either of them. Period. Your "friend" has double-whammied and embodied both of those today. Want me to beat him up as soon as I'm done ripping the arms off of Niki's ex?