I always get annoyed when people come here and apologize for venting. Makes me feel like I'm selfish because the thought doesn't usually cross my mind. It's a big part of why most of us are here, I suspect. So don't do it! haha.
You're in a tough spot to be sure. Don't let it dishearten you too much though. It's still early and time is on your side, no matter how it may seem. If she's going back without you, she's of zero status in the cult and the women will soon lose interest in her because she won't fit in to the couple's things and there's always that elephant in the room when she's around and it's just not the easy perfect situation that JWs prefer. They're not real friends, so if there's something that makes it hard they'll eventually drop off.
She's also mourning the loss of her mother, and the pull from the possibility (however remote) that they're right and they're the only way she gets to see her mother again is powerful. Maybe you can attack it from that angle, and help her remember the happy times with her mother but at the same time help her get closure? The cult is designed to prevent people from getting closure after a loss like that, and that's part of the pull. If you can help her to remove that, you'll get one of their biggest hooks out of her and she'll be happier too.
Make sure that you take care of yourself. Make it a priority. She'll see that you're growing as a person and she's stagnating and she won't want to be left behind. Make new friends for yourself and have them 'round and show her how much happier you are. Say things like "I never realized how great it could be to have friends that value me for me, not because we're just in the same group together." Lead by example and she may be won without a word.
It really sucks feeling so completely helpless and out of control in a situation like this, and it can really mess with your head. Try finding a hobby that you can be in complete control of. You've mentioned music - just force yourself to do it and you'll probably find that it comes back. Or find something else. Point is, when you're more fulfilled and feel like you have some power over one thing, you're going to feel better about everything. Your self worth goes up and you'll be more confident and your wife will see it. The more confident you are in your actions, the more she'll doubt her own when they conflict - that's just human nature.
It's clear that you love your wife greatly. I disagree with another's advice to go cold - I think your love for her is your greatest advantage over the cult. If you're cold her choice is between a superficially warm cult and a cold husband and that's an easy choice. Obviously it's up to you, but that's my take on it. I have to work on that myself because it's really hard to be loving towards someone who's giving you the silent treatment for skipping a meeting.
You've got a better chance at success than most, I think. You and your wife have been through a lot together, and in that crucible a powerful bond was formed. The cult may have a superficial draw right now, but I think you'll win. I wish I had the bond with my wife that I suspect that you have with yours.
We're all pulling for you!