How about getting your dad an escape room game that he can play at home? There are many board games and card games that simulate the experience of being locked in a room and having to solve puzzles to escape.
You can also consider gifting him an actual escape room experience if there are any local ones available. Or, if he enjoys puzzles in general, you could look into a subscription to puzzle boxes, where he would receive a new and challenging puzzle to solve every month.
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.