Do not think you can't lose someone you love in a flash, in a moment, with no warning at all. A close friend I love dearly had a major heart attack two days ago - I just learned about it half an hour ago via phone message. It was only luck that meant a friend got there in time - she was turning blue from lack of oxygen. It required a quintuple bypass, then another surgery to fix something.
There are old people you know, people you think could die any minute, and people you feel confident about, and she was the latter - active, enjoying life. No sign of major health problems. I guess I'm going to get dressed and see if I can wheedle my way in to see her.