It does bring things into perspective when you worry about your folks in situations like this. I had to be the bearer of the news to my mom about her mother. One of the worst things I've ever had to do....
P.S. I never knew my mom's father because he died when she was 16 (my mom) and my father's father died when I was 10. I wasn't even there because we lived in Germany at the time. He was so young and had so much life to live. Same for my mom's father. Count yourself lucky for knowing your grandmother as long as you did. I'd give anything to have known both my grandfathers in my adult life. Sometimes I think about what it would be like. You are truly lucky. *hugs*