My parents moved in with me after they retired, my wife keeps nagging me about little things about them specially about Dad, like why ur dad uses guest bathroom, he shud use his own Your Dad ate the meal i prepared for you why he watches tv till late night (though it does not affect her in any way) etc.
I have told her many times that you can't expect to change there habits at this age and these are little things.
What can i do about it?
My gwad! I feel for you. Hehe! If you take Dad's side, she will nag you more and if you take her side, your Dad might get hurt.
Maybe your Dad uses guest room toilet b/c it gets cleaned more often! Or maybe because the loo-roll is softer!
Tell wife to cook same meal for her FIL and husband. (As your Dad obviously likes the meals cooked for you better!)
Get your Dad his own TV in his room, so wife doesn't get bothered that she is missing late night Oprah. Lol.