So sorry to hear of your medical difficulties. Personally, I think that the more both you and your wife keep busy, the better it will be for both of you - physically and mentally. If you both still love full-timing and workamping and you feel you can still do it, I would say to keep going.
It sounds like you don't want to go back to a S&B so if you did so, you probably wouldn't be happy about it and would be more inactive which definitely wouldn't be good for either of you.
If you're not physically able to workamp possibly volunteering as campground hosts in some of your favorite areas or areas you want to see would work for you. Camp hosts in state parks typically don't have heavy manual duties and then your campsite will be free and sometimes even propane is free.
I'm sure your family would be more than willing to help when the time comes to seriously stop full-timing.
I, too, would recommend one more opinion on your medical condition and then perhaps you'll be able to make better decisions. Hopefully, your first opinions are wrong. Best of luck to you. Stay in touch.