I have an acquaintance who is convinced that Google ads stalk him because the ads make inferences yet shouldn't be able to, like offering flight prices from one

I have an acquaintance who is convinced that Google ads stalk him because the ads make inferences yet shouldn't be able to, like offering flight prices from one city to another he frequents when he's never done that search in Google before. I've tried to explain to him that people aren't actually very unique in large models, and there's probably several signals Google does have from his other searches to conclude he's interested in those two cities.