i have only just read this- and feel so much for you as i have 3 boys- 2 are have Asperger's and the 3rd is just 6 and seems to have it too.
something 'spooky' about how many AS kids start to notice themselves how they feel different at around 6 or 7. The party invites stop coming...and as others start to form 'proper' friendships ...ours are the ones left out.
It's not much help i know...but YOU are NOT alone in this....and nor is your son.....
Please give him a hug from ME and tell him that my boys feel just the same...so he is NOT different in my eyes.
It's gut renching to hear how he is so isolated at school and teachers aren't always aware of the ones who wander aimlessly around- minding their own business...they seem to only notice the ones causing trouble.
If you are relaxed about talking about this to his teacher/other mums...and you feel able to invite a child round who you or the teacher etc feel may be a possible friend...then your son will be in his own territory and feel safe....basically... i have to 'guide' my son's with friendships....they don't do it naturally...so like many AS parents i end up inviting people here for tea...and accept that the invite is never the other way.
My 8 yr old is frustrated that no-one likes his current obsession (yu-gi-oh trading cards)so i have started a thread about that hoping to find him some 'online buddies'
I wish i didn't have to be so involved...but like you i cannot bear it if my son feels issolated.
My 11 yr old AS son however...has occaisional knocks at the door to go out...and he declines...and they still call back...so i guess i have to accept that he is happy.....and liked. But when he was 6 or 7 it was a bad time- he withdrew to the back of the class...he felt so different.
So....in his case..he is now happy doing his own thing. He finds kids his own age irritating!!!