Is there any evidence that a healthy lifestyle actually increases lifespan? Most people who take better care of themselves don’t live that long. Why?
Juliane Koepcke was a 17 year old who was the sole survivor of a flight which was struck by lightning over Peru. The plane split in two and Juliane fell over 2 miles, still attached to her seat before smashing into the tree canopy. She survived the fall, and she then survived 10 days alone in the jungle, in a small mini skirt, with no glasses, and only one shoe. She had injuries from the fall, including one from which she had to pick 30 maggots. Having your plane split in half, 2 miles in the air and then being stranded in the rainforest for 10 days isn’t a good recipe for extending your life, but Juliane survived, and her survival may explain why your elderly neighbour survived so long too.
Luck.
Juliane got lucky. She shouldn’t have survived, no one else did and very few have ever survived from that height. But she did. Same with your neighbour, you can do everything wrong, you can be destined to die based on your circumstances but you might just get lucky.
There may be other factors, he might have great genetics. He may be extremely healthy in other ways. However someone unhealthy living a long time doesn’t show an unhealthy lifestyle promotes longevity, it just shows that when there are billions of people, there will always be exceptions.