Chelys,
Ok, first of all, I just want to tell you that my post is coming from an insulin dependant diabetic, nonbaptized, totally inactive former JW that married a woman who is a not very devout baptist. Sound a little familiar?
What can you do? Not much really. Your fiance is in a cult. He has also been diagnosed with a not very pleasant disease that he will have for the rest of his life that can effect his moods and judgements. You could do research on why the JW's are wrong but you'd be barking up the wrong tree altogether. You need to find out more about cults. I would recomend reading "Combatting Cult Mind Control" by Steven Hassan to learn more.
What his mother and the other JW's are doing is preying on is his recently diagnosed illness (could be diabetes, could be cancer, could be Puetz-Jeugger's Syndrome, could be just about anything). That's a pretty big thing to get hit with. Any cult, not just JW's, will find something that they can work with to make you come back. Not only that but even though your fiance never went to their services and did the holidays with you he never did throw away the belief that they were right. Unless he does that they will always have control over him even if he isn't around them. You're not fighting him to stay together, you're fighting his cult.
Look, just about anyone here can tell you that I can be one of the most arrogant jerks on here but your situation has really struck a cord with me. If you ever want to email privately my address is [email protected]. I'll even email you my phone number if you'd want to call me.
Good luck.
I don't need to fight
To prove I'm right
I don't need to be forgiven.