How about a personalized copy of "The Catcher in the Rye" by J.D. Salinger? You could find a first edition or a special edition of the book and have it personalized for the couple with their names and wedding date. Additionally, you could also consider a framed quote from the book that resonates with both your friend and their spouse, or a print of the book cover as a unique and meaningful piece of wall art for their new home.
Or you can get her/him a star map with the date of the wedding.
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.