Thank you for your observations and opinion, Elliott.
I have a couple more questions, if you don't mind.
I can see that my son has some traits of Aspergers, but there are other aspects that make me wonder if this is a complete fit.
My son does not have a fascination with objects or numbers. He doesn't notice "things" in his environment and isn't particularly interested in finding out how things work. He doesn't have a particular fascination with cars, trains, schedules, sequences, daily routine or anything like that. He has no unusual postures and is very athletic. He doesn't say the wrong thing in front of people or act inappropriately (other than being in his own world sometimes) and he 'gets' social humor, etc. He isn't a nerd, he knows how to dress appropriately for social settings and on a daily basis, he just doesn't want to dress to attract too much attention. (i.e. he doesn't want to be a hipster or too "cool")
In other words, isn't it possible that he is just an introvert with a bit of social anxiety?....or is that how you define high-functioning Aspergers?
In either case, we don't know if he is generally happy or deeply tormented, and don't know how to find out. That's really what I care about.
If it's something like Aspergers, and he is totally fine with how he feels, then I'm fine with that....I just don't know how to broach the subject to find out.