It sounds like everyone else around him has more of a problem with the way he is than he does. If he was diagnosed I doubt his opinion would change. A diagnosis doesn't mean that people will conform to what other people want of them. Probably the opposite.
I'm sorry if this sounds blunt but you seem to think that his suspected Autism is the cause of his opinion and not his individual choice. His "quirkyness" which you love him in spite of, is as much a part of his personality as his loveable side.
It sounds like you have fallen hard for someone who you don't have much chance of a future with. I'd stop wasting my time and find someone more compatible. You sound like you want things your way and he sounds like someone who wants things his way.
Another thing is that being Autistic is never an excuse for being a bit of a ***.