to be fair, most of the grandchildren of George V have made it into at least their late 70’s … of the ones still with us, Prince Richard is the youngest at 77.Not really King George vi was only In hid 50's when he died and his youngest daughter Princess Margaret was in her 70's, Prince Philip almost made it but didn't. The only one who has lived over 100 is the Queen Mother.
There is longevity in those genes, but they can’t combat lifestyle and virtually chain smoking for decades.