I haven't bought a gift for a man in quite a while. But when I had one to buy something for, I usually bought things that either he liked to wear(if you can't sneak and check the sizes of his clothing, yea, you will have to ask), something that had to do with how he spent his leisure time, something he liked to eat or drink(gift pack of tea he liked for example), or perhaps a fragrance that he liked. I'm sure you'll come up with something that he will appreciate.
