I second @avj, you should talk to an immigration lawyer and not just an immigration consultant. With all due respect to immigration consultants, the quality varies wildly. The relevant section that you’re likely concerned about is this.
You could search for law firms online but be sure to schedule a consultation with them before committing to using them. I found one online that seems to list Autism as one of the conditions that they’ve helped clients deal with. I can’t vouch for the quality of their or others as I haven’t had to use them.
The one thing that is to your benefit is that if you are a permanent resident, then your immediate family sponsorship is immune from medical inadmissibility on the grounds of excessive demand. So if you were to first become a Permanent Resident and then sponsor family you should be fine, I’m not sure if non-accompanying members are also subject to a medical though during the initial application.
Best of luck with your potential application in the future.