Are the people/professionals, who have seen him so far, experienced in
diagnosising autistic spectrum disorders such as PDD/NOS, Autism
Spectrum Disorder, Aspergers, High Funtioning Autism etc. If not I would be specifically asking for a referal to a centre/unit that does.
Google DSM IV for autism and read through the diagnositic criteria. Does your child have diffficulties in the three areas it mentions?
What type of school does your son go to and what country are you in?