My dad's absolute favorite is the Hoop-Dee-Doo. He spouts bear jokes all year long and was drooling over the fried chicken just this afternoon. I know that's 2TS, though.
A few years ago we happened to be there on his birthday, and he chose Tony's. He likes spaghetti and sausage, and we've never had a bad experience there. I know you said you were thinking about cancelling, and I'm not trying to talk you out of it, but suggesting you ask him for an opinion.
He left the decisions up to you, but have you asked lately? You don't have to go over menus with him, but maybe ask him what kind of food he might like one night.
Good luck!