Um.
I think I have to go with the odd word of caution about booting. While I'm not the best man about respecting differences in player and DM expectations and I do think this goes beyond the pail, I also think that booting someone is the solution that has the least potential for profit.
There are indeed a lot of interactions that go into a situation like this, and it's very possible that a small bit of compromise on a fairly unrelated topic could solve the whole issue.
There are people who are primarily unforgivable dinguses, but there are also very few circumstances in which someone who is being nasty isn't doing for specific reasons.
Sounds like this guy is feeling like he has no real power or agency in the campaign world or the make-up of his character. Since the rest of the party seems to be doing ok, this is probably a specific interaction.
It may be that the only way to really resolve the tension is to give something that you absolutely do not want to give him, but something like a prestige class seems to be a small sacrafice for someone who might otherwise be a productive player.
Otherwise I would recommend simply sticking to your guns. Eventually he will boot himself out. You'll look like the bigger man and he really won't have grounds to badmouth you to other potential players or actual friends.
edit for unread last message:
oops, missed your last comment. I'm in a situation where there are party behaviours I would like to change, and I can understand your decision. But I've also been the cause of situations where radical differences in gaming style resulted in some very interesting in game plots as either side attempted to correct the other.
I'm sad you'll be loosing a group, but maybe you guys can game in a different situation or with different roles. Adjustment and negotiation are the terrible sticky pit traps of the hobby.