Hi and welcome.
I never dreamt that my parents, with whom I was incredibly close, would choose to obey this man-made cult and shun me completely solely because I told them some of what is wrong with their JW religion--I was a card-carrying member. Partly, I wish that I had handled it all differently, but I know I would only have postponed the situation as it is now and was tired of pretending that I still believed it.
My point is, if you do this, you will lose your friend and eventually your job. The longer you can NOT care about that of which he is a member apart from work, the longer you will have him in your life, and as good friends are truly hard to find, I hope that is for a very long time.
The chance that he will listen to the facts and see it for what it is, is sooooo slim, you will only hurt yourself. And he will simply tread away in self-righteousness, gloating that he squashed Satan's attempt to weaken his faith, and he will never give you another thought. But, you will be crushed.
Be happy with what you have. That's my opinion.