THE CRUSHED- So sorry you are going through this enormous stress as you so accurately stated " brought on by the WT society ". You've had GREAT suggestions so far on both pages , especially by OODAD, Black Sheep, JGNAT , and Billy the EX-bethelite on this page.
I will second some of their opinions . DO NOT, I repeat, do NOT go to the elders to talk about this as they will only use what you know to separate and divide you from your JW wife. Your wife sounds as if she is HEAVILY mind controlled through fear and guilt instilled by the WT society. The suggestion to nOT bring things up until the mother in law is gone is an excellent suggestion too. What was the old Beatles song suggestion " mother superior jumped the gun " ? That's what's happening here. Your JW mother in law is trying to allegedly " comfort " your wife - but doing it in a way to reinforce your JW wife's allegaince and devotion to the JW cult, not you. Probably putting some pretty screwy ideas into her head for sure.
As Black Sheep said, you need to go slow. Don't bombard her with too much information or at this point ANY information as it will trigger her cult protection mode. The only reason your wife is scared $hitless is because she's been conditioned to be scared Shitless by the false ideas of the WT society of how " scary " independent thinking is. Her violent physical reactions, crying, throwing up - are an indication of how deeply she is indoctrinated with this muck.
As JGNAT stated, try to get her involved with ANY ACTIVITIES that don't have ANYTHING to do with the JW organization or WT society and avoid talking about the JW topics at all right now. What hobbies does she enjoy outside of the Witnesses ? Walking ? Running ? Shopping ? Go shopping with her. Antiquing ? Go to a movie, thrift stores, play tennis, anything to keep her mind off of JW topics. Your goal should be to access her authentic personality, not her cult personality. Understand this : SHE is the one with the mental condition right now, not you. YOU are thinking clearly, she is not. I highly recommend reading Steve Hassan's 2 books on mind control and how cults like the JW's, Scientologists, and Mormon's use insidious and tricky methods to control and manipulate your wife's personality. Information is power and if you understand WHAT makes your wife this way, it will slow you down and realize your reaching her isn't going to be a quick operation. It will take time and patience. Hassan's books are titled, " Combatting Cult Mind Control " & " Releasing the Bonds- Empowering People to Think for Themselves ". These books were a lifesaver for me when I stopped attending 8 years ago. Please read them. You will then understand the hows and whys of what is happening to you right now. Hang in there, remember we are here for you too. Many of us have been through this and are glad to assist you. Private mail me or anybody here if you'd like to talk on the phone, O.K. ? Peace out, Mr. Flipper