How about a trivia board game, such as Trivial Pursuit or Wits & Wagers? There are also a lot of trivia card games such as BrainBox or Timeline. You can even create your own trivia game with questions about your family history or his favorite topics. Another idea is to get him some books on interesting facts and trivia, such as the Uncle John's Bathroom Reader series.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.