Your worry about how your wife is going to hold up is a wonderful trait to have! So admirable! If you are able to support her, just emotionally, it will go a long way. Others here have posted excellent suggestions on reasonable paths to explore. Certainly, that disability qualification should be addressed again and again. Parents may be eligible for services and not know about it. Filing paperwork and making calls may be the kind of help your wife can give without too much stress. But you and she must discuss it and be quite clear as to what "help" means and how much is too much!
This is such a terrible situation--no winners here. More and more, there will be exJWs who will be helping out parents and other relatives who did not plan ahead. Good for you for making plans ahead of time for your retirement. You should not be guilt-ed into compromising it for ANYone!
Good luck.