Gosh , it seems like one of the family members should be able to look up info & find some sort of help.
as a kid gets big they don't always listen or do what they should...

[Autism Spectrum Disorders, or
Pervasive Developmental Disorders

Autism is a collection of behavioural symptoms, not a specific disease. These symptoms are found in several specific medical conditions as well as the autism spectrum disorders. The terms Autism Spectrum Disorders and Pervasive Developmental Disorders refer to a group of disorders characterised by delays in the development of basic functions including socialisation and communication. This group of disorders includes Asperger's disorder (Asperger's syndrome) and several other disorders in addition to autism. ]
http://www.thechildrensclinic.ie/autism.html#aspergers

But if he is disruptive, unsafe, or acting out in harmful ways maybe child services could be called and then he may get him the help needed...

Or possibly call the police if he is doing harm to himself or others, but be sure to tell them he is autistic- tell then many times, so if he isn't following their commands they don't shoot him.

It happens - they only know the person is not following commands and even worse if the person makes a wrong move.