I tried to reply to this and lost my entire post, so I'm going to keep it brief this time.
I have a 5 year old with Aspergers.
IMO you should fight the school on this! Educate yourself on yours/his rights, request and IEP meeting (which the school must do), find someone who can attend the meeting with you who won't back down, and request that they provide him with an aide (or at least a 2nd aide) in the classroom. Don't let the school take advantage of you, because they will!
Also, if they aren't already providing him with OT at school, fight for that as well. AND if your insurance will pay for it, you should get him a private OT also.
My son goes to a blended class, but all of the kids with special needs are high functioning. The lower functioning kids are either in the autism classroom or special ed (which my son was in when he was 3). He gets OT and speech both provided by the school and we do private OT and a speech group - which focuses on social skills training.
If you have any questions, feel free to email me.