I didnt read through everyones posts in the thread so someone might have said this.

If it was me I would call him up, and just invite him to a one on one session ya know. Just so he knows that you care. I mean just have it be you and him, just talking, he probably wants someone to talk to so that be a good thing for you to do. but whatever you do, dont force it on him to smoke. He may actually not want it right now.