That's a tough one, James.
My ex- jw stepson is a really kind hearted and honest person, intelligent and fun, who I totally trust and always enjoy his company. He's been out about 15 years. His 2 sisters are still jws and shun him and his dad (Flipper), except on rare unpredictable occasions. The jw's can be fickle for sure.
I used to look forward to getting to know his sisters thinking they would be like him. Now after 10 years being married to Flipper and seeing so many examples of crazy (and rather mean) behavior from the jw family, I kind of dread having much to do with any of them.
Flipper loves his daughters and misses them terribly - but I wonder what kind of people the cult has made them into. Would that change if they got out? I hope so - but I have learned to keep manipulative people out of my life after being traumatized by some pretty bad treatment years ago. Sometimes you have to be careful.
There is always hope to rekindle a relationship, it's worth a try. But not if it's going to be destructive in the long run.
Sure do wish you the best with this.