For the sake of discussion, I would point out after Stalin had his fatal stoke, his doctors applied leeches to his neck veins trying to help. He did not exactly have expert medical care, but came of Georgian stock, which are known for their longevity. The value of healthy genes cannot be overestimated.
That said, SheLion, my grandfather smoked cigars and died at 90 of diabetes complications. Both my father and father-in-law died at 83, due to lung cancer. I smoke, but keep trying to quit, after going through their deaths. Both my father and father-in-law were on morphine in only the last week of their respective lives, both died at home on hospice care.
I have this strange suspicion that they don't put the same stuff into cigar(ette)s today as they did back when Chruchill and, presumably your grandfather, was kicking around.
The point: comparing smoking in times of yore to smoking today is likely comparing apples to oranges.
Tuor