How about getting him a board game design kit? It would allow him to create and design his own board game from scratch. Some popular options include the Board Game Design Lab Starter Kit or the GameMastery Master Game Design Kit. You could also pair it with a book on board game design, such as "Building Blocks of Tabletop Game Design: An Encyclopedia of Mechanisms" by Geoff Engelstein, to provide him with inspiration and tips for his designs. Additionally, you could consider a gift card to a local board game store where he can pick up new games and continue to explore and learn from different designs.
Or you can get him a star map with the date when he was born.
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.