Sorry, I misunderstood because you said applying for a visa which is very different from PR. Was it recent? Are there any other health issues? If so you need to hire an immigration lawyer ASAP to help you respond to the PFL. You can overcome but you need good legal guidance to put together the response. You need to get your documentation together from your doctors and psychologists to prove that he will not be a burden on the system. Most Autism services in Canada are paid out of pocket and waiting lists are long so not sure how a burden.