Knifegill, I don't think they were all Jewish and Italian - three were African American. Also, Jewish is a religion rather than a Nationality. But if I want to look further, I may take the time to check nationalities.
Solstice, my grandmother's doctor said it's very common with couples who both live to old age, for one to die within 18 mos of the other. So, I'm not too surprised your grandfather's health went downhill after your grandmother died. Good on him for being so active! It shows that it doesn't have to be grunting in a gym.