I hate what I've become

I've been on this forum for a few weeks now, so I don't think I need to repeat the entire story of the last 15 years of my life here. Long story short, I'm 66 years old, been retired on SSDI for almost 10 years now, and suffer from chronic pain due to osteoarthritis, and idiopathic poly neuropathy in my feet.
From October of 2011 to November of 2018, I had surgery 12 times. I had 5 knee operations, 3 carpal tunnel surgeries, elbow surgery, 2 spinal fusion procedures in my neck, and skin cancer removal.
Physically, I'm now a shell of what I used to be, I have no physical endurance any more, I can't walk for more than 10 or 15 minutes without help, and I have balance issues as well. I'm not allowed to get on a ladder by my family for any reason now, which is humiliating.
I always worked a very physical job for over 35 years, which obviously has taken it's toll.
When I walked away from my job in July of '15, we had to sell our home and move in with our son and his family for 2 years. Retiring the way I did completely screwed my wife and myself over financially forever, we 'll never own a home again, and she's working to support us while I sit on my ass in the house dealing with the chronic, never ending pain.
I swore that I'd never become a fat old man when I was retired, and that's exactly what I've become.
I've decided that I'm done with the "specialist" doctors, I've had so many of them, and mostly what they've done is cost us money that we don't have. How can I lose weight if I can't even walk any more? I'm done them. I'm not going to bankrupt ourselves or our kids with more surgeries or treatments.
My life is pain, and pain just means that I'm still alive.