Things have changed regarding prison and written communication but my mate spent most of his 40's inside, the most precious thing for him were the letters, at first I found it difficult because I didn't want to write about anything good that was happening as it seemed cruel but eventually I got into it, just tell him how your life is going, good or bad, make sure he knows he can ask you if he needs anything sending in, not mobiles & spice though:).
Sounds like visiting will be difficult if he's miles away but if you think you're able then ask him for a VO once he's settled in.