On my dad's side, his mom died five years ago at 95. His dad died at 63 from years of smoking and heavy drinking. I never knew my grandfather, because he died of lung cancer four years before I was born. When I was a kid, I swore I would never smoke cigarettes since I'm convinced they killed my grandfather.
Dad is now 72, same age as McCain. He's still working 45 hours a week, but will retire at the end of the year. He is still very active, however. Earlier this week he and I put in a new ceiling fan at my condo, because we're getting ready to put it up for sale.
Sure, he could drop dead, as my dad's had health problems. His blood pressure went sky high in 2001, and he suffers from congestive heart failure, and he's still overweight. But he quit smoking 40 years ago and quit drinking six years before that.
Somehow, I think he winds up closer to Grandma's age.
The only reason why I state this is because of your argument. I think Dad got Grandma's genes.