Canada health care normally does not cover medication but price of it is regulated in Canada so it's generally cheaper than in the US. Most employers include a supplemental health insurance in their benefits package that covers things such as medication and dental so if you were living in Canada with your son and you or your husband are working, it would most likely be covered.
You can find Ontario Health plan at
http://www.health.gov.on.ca/english/public/program/ohip/ohip_mn.html