I cant get sraight answers

i have a 3 1/2 yr old son, who suffers (greatly) from uncotrlled seizures, metal retardation, developmental delay, and other minor problems. some of his theripist believe he may have autism as well. he attemps to be social, but has only a 4 or 5 word vocabulary. he does'n't play with other kids, or his toys properly. he will spin the wheels of a car, but not push the car across the floor. he has no fear. of anything. ever. he will walk up to strangers, or into a street. he likes to bang his head alot. he likes rough play. his pediatrition thinks he may b autistic, neurologist said "i don't know, iguess he could be" but never order any kind of test. what is your oppion? could it be autism? where can i get a test, and how?
- Thanks for your time
  Scared Mom