Bonz, I offer my prayers and a few suggestions.
-My main worry about getting older is making reloading mistakes. Make sure your meds don't mess up your concentration.
-Your wife can liquidate your guns without an FFL. It's mentioned in the "who needs an FFL" section on the ATF site.
-A friend of mine once sold guns for a widow. He talked to her about prices as neither wanted it to go on forever and they priced them accordingly. All he asked was first chance at anything he liked. You probably have a friend or relative who could do this for you.
-Finally about medical care. When the time comes for all of us to make the decisions you're facing, we shouldn't write ourselves off but we should be realistic. Palliative care may be your best option. It's not hospice, it's about treating you in a way that keeps you doing what you want as long as possible.