Asking this question after my grandma finally passed away this year at the age of 101 (before you ask, I'm fine, we're not really close because of family reasons).

As far as I know she didn't have any serious illness, no cancer, no organ failure. The doctors just said yep, she died of old age in her sleep. So what exactly happened to her body that led to death? And is it a peaceful death or a slow and painful one?