How long would JFK have lived if not for 11/22?

[Snowstalker Mk. II]

Setting aside all the alternate history questions of how John F. Kennedy's presidency would have gone had he not been assassinated, how long would he have lived? Four of his five sisters lived into their eighties (the other dying in a plane crash), and Ted lived to be 77. However, Jack also suffered from Addison's disease and chronic back pain and was, before and during his presidency, in much worse health than he let on in the media.

[Samof94]

Setting aside all the alternate history questions of how John F. Kennedy's presidency would have gone had he not been assassinated, how long would he have lived? Four of his five sisters lived into their eighties (the other dying in a plane crash), and Ted lived to be 77. However, Jack also suffered from Addison's disease and chronic back pain and was, before and during his presidency, in much worse health than he let on in the media.

He'd probably die by the early 90s and be in a wheelchair during part of the 70s.

[dw93]

At the absolute latest the early 1990s (and by that I mean no later than 1991). I think he'd be confined to a wheelchair full time by the dawn of the 1980s to boot.

[Atlas Has Shrugged]

I can't see him making it beyond '77/78ish if what I've read is true.

[Del Tachi]

Oswald killed Kennedy before his many medical ailments could.  But the evidence suggests that Kennedy's physical condition may have contributed to his demise.  On 11/22/1963, Kennedy was, as always, wearing a corset-like black brace as he rode through Dallas.  Oswald's first shot struck Kennedy in the back of the neck.  Were it not for the brace, which held Kennedy erect, the second, fatal shot to the head might not have found its mark. 

[President Johnson]

I'm going to differ from most predictions here and say 1975. Despite his age, Kennedy had a ton of health issues while serving and even before. He might barely have outlived Johnson, though dying of a younger age than him.

[Vice President Christian Man]

Another few decades if I had to guess