GTTM: Am sorry this is happening to you and your family.
I have been where you are too not long ago (3 months ago actually). What I realized quickly after a lot of independent reading on cults and high control groups was to avoid direct confrontation and arguments. It's important to be able to identify whether your spouse is her authentic self or in the cult driven mode before responding to sensitive subjects. I advise against using words like 'mind control' or 'cult' (hard I know in the heat of an argument) as they trigger thought stopping techniques in your "still in" wife. When opportunity presents itself, remain calm and make your points sincerely.
If you chose to stop being a JW, do you think you could make things work with your wife and kids if she choose to remain one?