Well, of course I cannot be 100% sure, but I usually don't see his other interests popping up on my ads. I must say that I am the person that doesn't use ad blockers or similar tech, as I want to see what is getting advertised on which content, etc. so I think that I am more aware than the average person of what I see and why. The holiday thing was extremely specific, it is a very small (<500 people) town in a very specific location, so unless you were not listening to our conversation and its context, it would be a very lucky guess to connect the needed dots (edit: grammar).