Have you read Steve Hassan's book? It is all about how to help someone you love out of a cult.

He uses interventions, that are somewhat like what they use for drug addicts etc. I really suggest you get that book and think over if you have the resources at to it.

I think it is possible when I was in the cult such a thing might have worked. I read the book a long time ago, but it is way more than the one meeting, there is prep for it to crack some chinks toward the authentic self inside.

I feel for you and the torture it must be. It is a terrible decision to stay or leave.