So don't! Don't let what he does affect what you do? I have friends on my email list I haven't heard from/talked to for years because they "dropped" me kind of like your friend because of their thoughts/ideas/feelings, etc. We can't do anything about what another is thinking/feeling, even if it is relating to us and the relationship we have/had with them. I'd look for other friends on there to play with and just kind of keep him there too, in case he was interested in playing with you in the future.