Most Helpful Girl
If you want to play it safe, just get a bottle of wine or what ever drink he likes - this shows you care and have acknowledge his birthday. Simple for both parties involved.
Though if you really like him and want things to progress further in the relationship and become serious, I get him something personal. I. e. has he mentioned any favourites hobbies or sports or books or films that you could get him something along those lines.0THIS IS NOT RELEVANT ANYMORE