John,
All of these posters make good points. At the risk of pulling this thread off topic a bit, I want to point out that you will hear a lot about unconditional love and friendship on this forum. As far as friendship goes that is a good thing, but I really wish my daughter and her bf would break up. They are far too serious for their age, and the cultural differences just create problems, and he would still be all conflicted even if he left his religion. Can you tell it is a long time since I was 15? lol
So many here have talked about how difficult it was when they left the JW, and some of it had to do with the lack of "outside" friends, and the inabliity to form relationships with worldly people. You obviously care a great deal for this person, so just be a good friend, and someday you may have made a bigger difference in his life than you would have expected.
Do you know if your friend has been baptised? That may be a turning point in your friendship. There would be a lot more expected of him as far as following the letter of the law, if he was baptised.