I guess it's part of the cycle of life and experience. 

When we're kids, we have not a worry in the world. When we're young, we think we're virtually immortal and do "whatever we can" without regard for consequences... and we may even think of older people who are "taking care of their health" as paranoid or obsessive.

My first serious wake-up call was my cousin Brian who seemed to be a happy and balanced person; in his early 30's he keeled over and died for no reason at all, leaving a wife and two young kids. 

I'm glad you got to experience that level of closure with your friend... that's pretty awesome, not to mention *rare.*