Hey Brian,
This is a tough situation. My advice would be not to come across to your wife as critical of the organization as it may cause her to become immediately defensive. I would suggest pointing out the many failures of the organization disguised as questions to make her think. (generation change, blood doctrine flip flop, false prophecies of Armageddon, etc. I would also show her the YouTube video regarding the ARC and watch Geoffrey Jackson make a fool of himself and deny his faith. Hopefully these things would hit a nerve. Take care.