Before my last colonoscopy I was talking with a guy whose 84 and he says "I don't have to do those anymore, I'm too old!" I asked my colonoscopy doctor about that and he said "Yeah, people are being told that but it's wrong. I had a guy whose over 90 in here 2 weeks ago in perfect health who has a huge cancer in his colon that will kill him and if he had been tested regularly we would have found it and prevented his death from colon cancer."
Sure, but the dude's 90 already, something is coming for him sooner than later. My wife's grandpa got a serious infection from a gall stent that came loose. They got another one in there, and a few weeks later the replacement one came out, once they got that sorted out, he told them no more stents. No more procedures. Requested a hospice bed to be delivered to his daughter's house so he could wrap up his affairs and pass on, 86 years were enough for him. He didn't care to spend his last months in a hospital to try and stretch for 86-1/2.
Might be your 84 year old buddy is satisfied with his life and doesn't feel the need to cling so tightly.