As Natalie mentioned above- if he is STRICT Kosher..then he won't eat anything you bring in because it is not prepared in a kosher way. They use seperate sinks, seperate utinsels, seperate cooking surfaces, seperate dishwashers, seperate plates- nothing can touch. (and the list goes on and on) it's extremely complicated to make an all-kosher meal for a very strick kosher jew if you don't have a kosher kitchen. So it's not just the actual food- a large chunk of why he won't eat what ya'll bring in has to do with the storage and preperation of the food. It's nothing personal
/ What i'd suggest instead is what some have already mentioned- go to your local Kosher deli or synagogue (some may have special hours during Hanukkah) and order a dish or two from there.
-Oh, and while you're there- definitely pick up some of the bread or pastries!!!! They're do die for
That way he can enjoy the pot luck too and rest assured that he is keeping Kosher
/ You are such an awesome person to do that!!! I would love to work with you
You are gonna make his day!