Sometimes the best way to break through a JWs programming is in a calm & diplomatic way..
Lets just say a cup of coffee at the restaurant.
You can show them all the facts. Be as calm & polite as possible.
Being argumentative strengthens their resolve & mindset.
Be calm & polite. Ask them questions and make them think. They will often give contradictory answers. Leave this with them.
This leads to cognitive dissonance. Then....doubt.;)
I know. Its what I experienced. ;))