Former POWs have a very high risk for heart attacks and strokes. McCain was a POW for half a decade.
The party professionals still have it in their power to CREATE A CANDIDATE everyone can vote for and put an end to this nonsense.
Will they do it?
Probably not. That's why they're going to be unemployed by Mid-November this year. That's why the Republican party, at the top, is called the Stupid Party.
McCain’s Mother is something like 94 years old, so he has the longevity genes.
But that said, he obviously will need to pick a strong person for VP, who can take over, should something happen to him.