How about a U2 T-shirt or hoodie? You could also consider giving her/him tickets to a U2 concert or a CD or vinyl of one of their albums. There are also many books about the band's history, such as "U2: A Diary," which could make for an interesting and meaningful gift. If she/he is a fan of any particular member of the band, perhaps you could find a special item related to that person, such as a book by Bono or an Edge guitar pick. You could also consider getting her/him a personalized U2 poster or wall art.
Or you can get her/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.