Hey Joakim,
TBH this sounds more like change anxiety than a legit concern because assuming I’m understanding you correctly he is complaining that 50 search results isn’t enough and then that he doesn’t want to search through hundreds of posts in the same breath.
I’d like to think that someone would find what they were looking for within 50 results and if not then the search should probably be refined!
Fear of change is totally legit. Perhaps we could approach it by selling him some of the benefits of the move. What platform were you on before?