This account makes me ill. I am sure that your daughter is sorry for whatever got her DF'd (if only because she messed around with a jerk JW), and between her and god, there are no hard feelings. I think your wife needs to have pointed out to her that getting back to the Bible, your daughter is morally clean. YOU and your wife know what's what and you have your OWN consciences that can be clear with speaking to your daughter. Can't you find a nugget of even scripture to get your wife to thinking about this. . . or as head of the household why can't you declare WHAT is necessary family business. Besides the WT made up that stupid condition? This is between you and God, not you and the congregation-they don't know her or care about her.
Your wife must be really awesome, amazing, beautiful, wonderful cook provider and (otherwise) the kindest person in the world for you to put up with this nonsense about your daughter and letting her control your relationship in that way. That is heartbreaking, even if daughter knows you are on her side internally, your visible loyalty is being given to that organization. It must be a heartbreaker for her and is telling the kids a lesson about grandma and grandpa's religion that is a true but ugly witness when they know they have a good mom who is loving and kind.