If my stepmom has property in Canada, would rights to survivorship apply or would that be different since it was owned that prior to the marriage?

My father married a Canadian citizen 30 years ago. He owned his house but within the last 5 years, his wife insisted to be out on the deed. I was under the impression that the property would go to the survivor upon the others death. I don't have a close relationship with my step-siblings as they live in Canada. My stepmother has recently become ill and the behavior of the said siblings has become very peculiar (they have stopped talking to my father and refuse to help him while they are staying in his house). Is there something we should know regarding if things are handled differently concerning Canadian citizens? I want to make sure my father's interests aren't going to be violated if my stepmother should happen to pass away before my father. She did not add my father to the property deed on that house. We aren't looking to profit from either of their deaths. We want to make sure upon death there is no confusion over who is entitled to what.