Oh, forgot also... his excuse for doing all of this is that he doesnt know he's a psion... he just thinks hes "really charismatic"...
So I did read pretty much the entire thread, and would have to agree with most of the advice.
Here's my two cents.
I've been in this group situation before. Honestly reading your posts triggered a ton of old gaming memorys. I know this player. Over the course of my gaming years I've had to deal with 3 different people like this. This is just an assumption, but I'm willing to guess he will fudge his rolls a bit also.
Anyways thats besides the point. This dude likes to play dirty, and you will have to play dirty as well. Since talking to him isn't helping, and he will remain in the group pretty much no matter what. I'm guessing the best fix would be to have him play something that can't do this anymore.
This is one of those rare occasions, when you will have to sink to his level. Here is a couple suggestions on how to deal with it.
If he can use retarded in-character rationalization then don't be afraid to give him a taste of his own medicine.
I'm guessing you don't really have to protect him in combat.. Try making some dumb decisions and drag monsters over by him? You could fall asleep on your watch, maybe you guys will get ambushed and he will die.. lol
Buy some poison and rub it all over his sleeping bag..
Does the dust of disturbance work for a psion? Do they need undisturbed sleep to regain powerpoints? I don't play psions so idk..
Take a level of barb or frenzied beserker and rage on him? Get leadership and have your co-hort do stuff to annoy the player, when he finally uses a power on your co-hort. Either have your co-hort seek revenge, or your PC slap him around a bit for using a power on your follower?
As I quoted above, he likes to pretend he is Role Playing his character right? He says, "no no.. my guy just thinks he is charismatic."
Well just be equally as absurd.
If he ever trys mind control on you, and your character realizes, just kill him and say " oh in my backstory my character was abused by evil casters. and every time he gets something cast on him, that he thinks isn't friendly, he kills the caster because it triggers a phobia" or some bull crap similar to that.
Hire someone to kill him?
I realize how childish all that stuff is lol.. but sometimes when rationalizing wont work you have to resort to drastic measures.
Good luck dude.