I'd combine two sugggestions made by several posters
After careful thought and prayer we found. . . But involve her in your research and thoughts. Teach her to spot logical fallacies in other slanted literature such as ads and infomercials and let her connect the dots in the wt "literature". Read Bible passages together and discuss how something in the wt material could have (or couldn't!) be derived from them.
Also explain your own feelings when you discovered these things.
A bit of work, but cult-proofing is a good idea with still-in relatives around.