In 2014, my siblings and I had a similar experience. Dad had undiagnosed dementia at age 91. It was obvious. He stopped paying his bills and refused our help when we offered to cut the checks and he refused again. He was a recording loop of whatever he heard of FOX News. He let his dog shit all over the place, including our mother's $40,000 Persian rugs. And he yelled at me when I tried to pick up the dried shit.
He shouldn't have been driving. He had a number of fender-benders. (He paid them off ironically, to avoid tickets and to be reported to the DMV.) I saw him pull out of the driveway and start driving in the wrong lane. The discussion of taking away his keys came up but we all agreed that he'd go out and buy another car.
One day, he stopped for gas. And stepped on the accelerator instead of the brake. He rear-ended a van in front of him. Maybe 5+ mph. But his car had no airbag and he wasn't wearing a seatbelt. His chest hit the steering column. And he refused the ambulance. He took a taxi home as his car was totaled.
Dad tried to sell his wrecked car ASAP to get rid of "the evidence". But he died a week later. Because he refused medical attention and didn't see any of his doctors, he was undiagnosed with a partial aortic tear, meaning the aorta had somewhat separated from his heart and he was having a slow bleed into his chest.
One week after the accident, he had a terrible backache (which he didn't tell any of us about). He made an appointment with his massage therapist. And you guessed it -- the massage hastened his demise. He got home, had trouble breathing, called 911, but it was too late.
Jr. and Eric may be worried about intervention as their father might erase them from his Will. Got news for you Chumpies. Our father disinherited ALL of us. We should have tried to do more. We had the clues. But we were worried about "retribution". Little did we know, Dad already had his retribution.