HeyThere, the work of Steve Hassan, my own exited husband, and recent articles indicates that direct confrontation rarely works against a firmly held erroneous belief. You've seen this in action with your study leader. As soon as the cultist starts repeating "I know it is the truth" or something similar, it is the cultic part of the personality trying to reassert itself.
As counter-intuitive as it may seem, the fastest way to help a person give themselves permission to look at alternative viewpoints is talk about NON-DOCTRINAL stuff. Address their natural selves, remind them of successes and interests in their past, their likes and personality. A confident, relaxed person is better primed to look at new information.
Then, don't force-feed your discoveries. Just insert a question or thought for them to mull over.
I strongly suggest you read Hassan's latest book before you try and sway your husband back out of the Witnesses.