How about a personalized crossword puzzle book for him? You could create a book filled with custom crosswords based on personal topics and interests that you and your son share. Another option is getting him a subscription to a crossword puzzle magazine or purchasing a crossword puzzle board game that you could both play together during the holidays.
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.