I absolutely believe that it is possible to help your loved one. Jesus rescued me from the organization when I realized that He was not my mediator.
Get the book by Steven Hassan along with David Reed's http://www.amazon.com/How-Rescue-Your-Loved-Watchtower/dp/0801077524
The first thing I realized, actually, was that Jesus promised to save me from the tribulation! All JWs are scared to death of the great tribulation and armageddon, so I would start there. It took me years from that point to actually realize that the JWs did not have the truth at all.
I think that getting JWs to realize that Jesus is not their mediator is very important, once I accepted that Jesus was my only mediator He was there to help me and everything else fell into place.
The doctrine of the 144,000 anointed ones is another to tackle. Along with those, they need to realize that as Christians we already have eternal life. We don't have to endure test after test. JWs have also been taught about a paradise earth, so that needs to be explained.If you read Revelation 21:1-4 and take God at his word, then heaven and earth will be one!
Pray about which of these points might reach her the most. Also remember that we are engaged in a spiritual battle, so pray that the scales be removed from her eyes, and her spirit of oppression lifted.
Most JWs have to have the contradictions in their literature shown to them, not just scriptures.
I will be following this thread, dear one, and will continue to post as I find things that will help. I don't know how to send privately?
Your sister in Christ,
SOG