Bite the bullet and expatriate them if you can handle the costs before your transport window closes [1], versus them declining destitute in their home land where you have no control if the situation deteriorates rapidly. I'd plead your case to whomever in the Canadian [2] and Russian governments will listen due to the situation and it being a compassionate case/allowance (providing elderly care close to family).
A sibling comment indicates OHIP wait periods no longer exist. Flex whatever social and consular assistance you can get, this is what they're there for. Don't be afraid to say "I need help, what can you do to help?" I'd expect more flexibility and support available during an active conflict.
EDIT: "4 independent sources I have say that the Russian border shuts down in <48, probably less than 24 hours. If you are in Russia and you can leave, leave now." -- March 3rd, 2022 9am [3]
[1] https://ru.usembassy.gov/security-alert-u-s-mission-russia/
[2] https://travel.gc.ca/destinations/russia (Consular assistance, click Assistance on horizontal nav->"Moscow" dropdown)
[3] https://buttondown.email/guzey/archive/4-independent-sources...