3rdgen: At age 60 I gave up trying.
That was the only good news in your otherwise depressing post.
JW parenting is simply abusive. To explicitly say that your love is conditional, to constantly threaten your children with emotional abandonment and isolation, this is horrible.
To ostracize and shun a person is the second worst thing you can do to them. It's even worse than murder. The only other thing that is worse is physical torture.