Something he can use just for himself to show him you value his friendship but respect that he is his own person. For example: * A professional massage * A hard cover book on a topic you know he likes * Quality headphones or ear buds * A classic safety razor from a European brand like Merkur
When I make gifts for my friends I always get a few pictures of us together and make a collage with words or phrases that describe them and our friendship. I am tremendously amazed by artwork at http://www.photoartomation.com . They convert photos into beautiful art. It always works for me.