I learned long ago that there is a certain nobility to the work that's necessary to keep the trains running and a pride that comes with doing it well. That kind of work rarely gets acclaim, but when it's not being done, people notice. Quickly.
I agree that the health exposure someone in their 70s is creating should be part of their decision, but I can see IL's friend choosing to work both for the occupation and for the ability to make someone else's day when they reach for whatever he has put on the shelf.