I'm not tarring anyone with any brush, I'm over 50 myself, it's a simple fact that we get older, and that brings the risk of illness and death, regardless of how fit we are. My parents both died around age 70, and had no health issues until all of a sudden they did have health issues
I know that a lot of people think that if they eat the right stuff and exercise a lot, they will live to be 90. Sadly it's untrue, we lost our fit as a fiddle, slim 45 year old friend to cancer last year within months of diagnosis.
I'm a fan of a 60 year old musician, this year he had a sudden heart attack, and nearly died, even though he is super-fit and does triathlons.
So, there's 2 points - as an older parent, you need a plan to support your kids if you don't live to be 80+, and also it's worth considering what age you will be at milestones in their lives.