The US doesn't care at all if you have a Canada PR card or not. They go by your passport only.
Somebody who becomes PR of Canada needs to live here for 3 years before applying for citizenship. People who are 55 or older do not take a citizenship test but they might have to do an interview, see
http://www.cic.gc.ca/english/information/applications/guides/CIT0002E5.asp I think she should better learn English if she is planning to live in Canada. Otherwise she will be completely dependent on her husband, assuming they are from the same country so they can communicate. What if her husband dies, who will take care of her then?