How many times and year, and how many months at each visit, a usa green card holder live in

Question

canada-if he is also a canadian citizen and senior citizen..

Answer 1

You are looking at this the wrong way.  If the immigration officers feel that the US is not really your home, you can lose the green card at any time.  Officially, if you are out for more than a year, you will lose it unless you have gotten a re-entry permit before you leave the US.  Absence of greater than six months will cause some intense questioning on return to the US.  Filing taxes is a great way to demonstrate that the US is your home.  Citizenship and age are irrelevant.

Answer 2

The green card holders are allowed maximum period of 1 years out of USA ( but usually immigration officers do enquire if they are out for six months ). Same rule applies to Canadian citizens if they hold Green Card.