Welcome to the Forum, hopefully you will get the benefit from some other people's experiences here.
From the sound of it every member of your family needs support. Obviously your wife needs specialist support for her addiction, and medical support for her back and hip problems - and sadly also for the physical effects of long term alcohol abuse.
May I ask why she refuses AA? Is there a religious objection or simply not recognizing there is a problem? If the former there are alternatives. The same with medication, do you know why she refuses that?
You yourself need the support of experts and those who have to live with someone who abuses alcohol, and that actually can be a help. I suggest you talk this over with our 24/7 Help Line on 1300 22 4636 and see what is available in your area.
Of course your kids are petrified, from your post it sounds as if a break up really could happen. Do you have any family who can give them comfort and support - even refuge - at times?
While it is a big downside I totally understand your position with work, if you have no alternatives then you have to keep going. May I ask how your wife and kids get on while you are away? Does her drinking lessen?
Trying to keep the peace when someone becomes drunk and unreasonable is just about impossible, and although you might find it very had removing yourself during the worst times might be an option. Your anger, even if totally justified, is merely fuel and upsetting to onlookers.
Are there times when your wife is reasonable?
Maybe one of the reasons your wife is talking of leaving is if your youngest sided with you, leaving her isolated and hurt.
Sadly I suspect this is a worsening situation as your wife's health deteriorates, I've talked of family support for your kids, is there anyone for you, a sibling or freind perhaps? Facing all this on your own is terribly hard. Then again maybe if you wife had a non-drinking friend close to her that might help too.