Referral/Information Sought for a Special Needs Guardian

I have a unique question, does anyone by chance know a lawyer that deals with special needs/intellectually disabled individuals as their guardian? Specifically, PC is a child (parent would be client) that was told they were not autistic by the school and therefore the services were denied to them, although the child is severely autistic.

Even if you do not know a specific attorney to refer, does anyone have knowledge in this area or any recommendations on the best way to proceed for the parents? I’ve done a fair share of research but nothing concrete regarding this particular issue. Looking forward to hearing if anyone has dealt with this before.