Thank you for your comment.. At first glance, using the UCCB might actually work. The basic criteria could be if you are under 18 and eligible for the DTC. This would cover kids with Downs, ASD and other conditions that qualify.

As you stated, the tax code is not the best way to deal with this. BC, for example,  has its own Autism Funding Unit that covers this sort of thing very effectively since the funds are used exclusively for tutoring - including swimming lessons. It's not a bureaucratic Leviathan by any means. Furthermore, the Surrey school district provides full time in class one-on-one support by qualified people for kids with ASD and other disabilities. The results are astonishing. It doesn't come at the expense of the other kids in the classroom either. 

No other province does this as far as I know and, judging by most of the comments on here, I can see why.