So long story short, my wife and I are in Canada and for the past while her father has been coming from abroad on a TR Visa and visiting, staying 6 months then leaving as required, until 3 years ago when my wife had our first child and he ended up staying to help. She's had PR since 2015 and I am a Canadian citizen, who sponsored her. We would like to have her sponsor him for PR, and we have good income so it should be okay on that front, but if he's overstayed his visa is it a bad idea to do so?