I think if you were there for your friend, and just displayed kindness at all times, they would soon know that it was more than friendship.
actions or like buy him something small for a friendship gift. make if you need to but don't go overboard.
You shouldn't. Unrequited love is the most practical variety. You get to enjoy the intoxicating highs without any of the complications of a reciprocal relationship. You won't act on it for fear of losing that.