My two cents...
I am an awake elder that started learning ttatt 3 or 4 years ago. I still serve because my stepping down at this point would send alarm bells to a few people I said too much to (like my wife). Plus it buys me protection from the other elders for now.
Anyway, to answer your question, I have recently as of yesterday had a conversation about the "truth" with a long time friend. I didn't say too much hopefully, but got close to the line with him. He is full in but not a servant.
My conclusion after that conversation and observing his reactions to things that came up, is that the attachment to the religion and the ideology is emotional. That point has been made already in the previous posts. I would add two things.
1) The reason you can't predict what will awaken someone is that you can't know what emotions specifically that person has for the religion. Emotion is nuts. It is unpredictable. For instance, if you found out your friend's spouse was cheating and then you told him or her, they might refuse to believe it and blame you for trying to wreck their marriage! Same with someone's religion. They are "married" to the organization. You are telling them the org has cheated on them. It can and often does get nasty.....
2) Since we are dealing with emotion, I think the best bet to move emotion is for a person to come to find out things about the org that are emotional for them to find out.
For instance the procedure for dealing with an 8 year old boy that gets molested in the congregation by his father. If the father denies it and there are no witnesses, the org does nothing to protect that poor little boy. No cops are called. No social services are called. No judicial hearing. Just a note in a file. 8 year old boy goes back home with a molester. Siblings aren't protected. Children in congregation aren't protected. Children in community aren't protected. All the while, the child thinks Jehovah is going to help him now since he prayed and went to the elders instead of his "worldly" teacher at school.
Anyhow, sorry to get long winded. Good luck with your family. I am working on a scheme myself to get info to my wife in some way that does not link back to me. Haven't figured it out yet, though. I tried the direct approach a few times and got backlash like I am the Devil himself. Freaky stuff actually.