All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If your health problem is as you mentioned and there is no hope to get cured, then you should feed a needy Muslim from the food that people in your area eat most of the time.
If you cannot find needy Muslims in Canada, then you can substitute the food by Canadian Dollars and send the money to needy Muslims somewhere else.
But if this health problem can be overcome, then you should make up for the missed days and you are not asked to feed needy people.
Allah Says (what means): {… but if any of you is ill or on a journey, the same number (should be made up) from other days.} [Quran 2:184]
Allah knows best.