So Australia has nothing to do with Canada. You are getting us involved in a non Canadian immigration issue. Autism is not a barrier for Canadian PR. What is your CRS score?
@Ritt
Ditto! What I can say is this (hopefully it will save you some money, if you want) :
1. Get your application in order, all documents collected etc.
2. Get you case reviewed by a consultant or a lawyer to weed out any obvious errors.
3. Apply.
4. Incase they send you PFL for medical inadmissibility, approach an expert lawyer to get it turned around.
PS: do remember, to mention any PR/visa refusals (like your australian one) in your canada application. That can mess up your application if you do not mention.