I am very lucky, and one of very few who's grandparents on both sides are still alive at my age. The issue with that is as age continues the threat of having them all go at the same time becomes truer and more realistic.
My grandfather on one side was given 6 months to live in August due to cancer. He is still here, 10 months later, and now starting to slow and feel pain. Taking it day by day.
My grandmother on the other side has just today suffered a heart attack. I sit wallowing in my tears after hearing that news...trying to remind myself over and over how lucky I am to have them still and that they've all lived very long amazing lives. It's not doing the trick...I don't feel any better about it. :(