Has anyone had success in talking to a relative and saying SOMETHING to get them to THINK for themselves?
No. No more success than trying to get an alcoholic to stop drinking or a drug addict to quit taking drugs. She won't see or hear what you have to say until she's ready and when she wants to hear it. Otherwise, you are wasting your energy and time.
I left 13 years before my wife. In those 13 years I argued, I reasoned -- I tried everything I could think of. Most of the time she'd say she agreed with everything I said but she'd still go to meetings and out in service. It wasn't until she found a reason to leave that meant something to her that she finally made the break.
My best advice is to get on with your life and do not wait for her. Let her know you are not excluding her and that she is welcome to talk to you. Exiting has good and bad sides. Freedom is part of the good; losing family is part of the bad.
Chris