Married, but living in two countries. Crazy?

It is very confusing to say that my mom needs to stay both countries. She have a choice to remain one country but it was too late . She first got PR in US then, Canada and then finally, she became a US citizen. She has been employed in US but not anymore in Canada, does she has to declare her tax in Canada too?

One time also, she was questioned at the border about her residency and advised to give up one of them. For me, I like the health benefits that my parents have but I don't know what to do about it concerning her status. My mom wants to stay here in Canada in the future but for now she comes back and forth. Since she is holding a US passport now and not anymore her (country of origin passport), is this will be an issue for Canadian immigration when she comes here? Thanks Steven for all the response you did, I really appreciate..

Unless your mother gained Canadian residency thru marriage to a Canadian citizen, AND if she remains married to and living with that SAME Canadian, she will be able to keep her LPR status.

However, if she gained her Canadian residency thru any other means of immigration, it is likely void now that she has moved to the US and got citizenship there. There is no way for her to keep it if she is living in a different country.

had she applied for Canadian citizenship before she moved to the US, then she wouldn't have a problem.

You can have dual citizenship, you can have citizenship of one country and be resident in another, but you cannot effectively be a resident of the US and Canada at the same time, nor would you want to be because you'd face dual taxation. Anyone claiming Canadian healthcare would be deemed resident by the CRA because only residents can get it.

Thanks a lot for you both (Steven and Reba)..