I always thought him to be an ENFP, but I'm not so sure now.
The reason I always thought he was an extravert is because he certainly isn't shy. In fact, we met because he practically forced me to be his friend. Haha. When he's in a good mood he talks almost non-stop.
But, I haven't seen his introversion at all until recently. He posted an agitated facebook status that said "No, I'm not mad, I just don't feel like socializing right now. Get over yourself." He's never really struck me as a "hang out" kind of guy, either. He doesn't text or instant message or whatever as most extraverts supposedly do.
Also, I've noticed that in his relationships with women, he doesn't really seem like a feeler. He's loyal and warm, but he's not at all "schmaltzy" like feelers supposedly are. In fact, I think he's terrified of any kind of sentimental displays of affection.
A little more about him so it'll be easier to type him:
He has a very extensive vocabulary. He uses big words a lot, especially in text. Sometimes I think he uses big words just to throw people off.
He's very quick witted and has a very eccentric sense of humor (one of the reasons we get on so well.)
He often complains that no one "gets" him.
He loves to write. He wants to be involved in music, but he's more interested in the business area of it, rather than the writing and singing part. He wants to be in production or management.
He can be a little selfish, but he can also be very selfless when need be.
Very loyal to his friends. His girlfriend tried to pick a fight with me (she hates my guts) and he took my side.
He's not very good at criticism.
He's a very loveable person. Well, actually, people either love or hate him because of his sense of humor.
He's got no problem talking to other girls about his problems with women. He always comes to me and asks for advice when his girl's wearing him out.
Anyway, I still think he might be an ENFP, and he was maybe just burned out that one day he told everyone to leave him alone.
I've also considered maybe INTP or ENTP. Not sure, though.