Sorry, maybe I shouldn't have said diagnose, I am looking I guess more for ideas as to what possibly could be going on. I know it is not really my business, but I just really would like to try to guide him to some kind of help so that he can live a more fulfilling life, because living in his parent's basement afraid of social interaction and all the 'losers' out there is not the way for anyone to live.

You are right though that maybe all that I should do is sit down and talk, I have tried digging and asking some probing questions but he usually just jokes it off or gets really defensive, I have to be a bit more forward with him though and try to actually get him to open up (if he wants to). I am great at listening to him complain about his problems (sometimes a bit too great at it, I feel like an enabler often) but I think he should be focusing more so on the root causes than just issues he has with different individuals.

And absolutely I don't want to push him toward my lifestyle or anything, he is much more in touch with activities outdoors and mechanics and video games, none of which really interest me, it is just tough watching him think that anyone who isn't just like him (and me for some reason, I guess only because I've always been a good friend) is a loser or a weirdo and not worth his time, which unfortunately leaves him with a very small pool of people.

I will try to grab a beer with him soon and sit down and talk face to face and see if he wants to open up to me. I am wondering though if from what I have said if you would have any rough ideas of disorders that I could read up on (you seem to be at least somewhat knowledgeable) and see if they match up with him at all, only because that may help me have a better idea of how to handle this issue.

Either way thanks for reading and responding, it definitely puts me on a good track!