Ask him what appeals to him with the JWs! Don't assume you know. Maybe for him its different than it was for you.
Point out to him how the JWs make your feel "stupid" because a lot of their dogma can't be explained. (It's their weaving of facts & fantacy) Point out to him, very gently, some inconsistencies that you are aware of.
Also show how they are a fear based religion (Armagedon, not havning family members, etc) And how they use guilt to keep people in their place.
I think a quick summary of the JW's in Apocalypse Delayed was good.
But find out where he really is at. Then go from there.
Good luck.
Joy
also show unconditional love and point out the JW's don't.