Mr. Flipper,
I agree with darkuncle, she is in defensive mode right now. Anytime they are challenged they circle the wagons--so to speak. Maybe after the dust settles he could just highlight the flip flops in policy and how they have cost people their lives.
A JW Mom can play the guilt card like a pro. Our mother (org) did it all the time, remember?
Your son is doing fine so far, but he may need to use the kid gloves for awhile. If you push a believer too far, they tend to kinda snap and not be able to reason( as if they really can in the first place without magazines). It would be great if he could give her a research project that would make her dig out the old bound volumes and see the differences between then and now.