There's your motivation to get over this as well as you can. Get the guilt load off your grandson.

I sympathise to a degree with you. I still have apprehension about descending on winding roads when they are wet. I probably won't ever go as quickly down them as I did before I came off and dislocated my shoulder eight or nine years ago.

But, that incident didn't stop me from riding. It just was that I had to do a lot of it before I was more comfortable in certain conditions.

I'd also get rid of your current tandem. It seems to be a liability, for reasons I don't know, but I'd venture to say that two-wheel recumbent are more difficult to balance in a straight line let alone a tandem one.

My feeling is that once it's gone, you've got a clean slate to start again, and the temptation to persist with getting a successful ride in on it will disappear. You can then concentrate on finding the bike that suits you.

Also, have you had a check for osteoporosis?

But under any circumstance, keep posting here with your advice and experiences.