I'm trying not to be mean here, but think about this for a moment. What does he write to you that you like? Wouldn't that be the same for him? What do you think that you could tell him that he would enjoy reading about? Don't be so afraid of thinking this through. Are you the type of person that has a great sense of humor and that's what he likes about you? If not, what else about you sparks his interest? That's how you get your ideas - you let your imagination run free.
