My father used to smoke since he was 15 and kept smoking even after a heart attack when he was about 55. He had a stroke when he was about 60 and he automatically stopped smoking, completely. It was too late for him as he had already contracted emphysema quite a few years back. I have read some where that a type of stroke will actually reduce the nicotine dependence (but I am not able to find any references right now). Looks like something like that happened or the second stroke was a big motivating factor for him. I am not telling you that your grandfather has to go that route, I am just suggesting that it is possible to quit at any age. Hope this helps.