A recently-retired friend decided to take up EMT training. He wants to remain a useful citizen. Thus far, he loves it more than he ever liked his job. The chance to save a life is an appealing thing, while learning all sorts of new skills.
As an MD, I have to admit that these people can do things that I have no clue about how to do. Never learned, or can't remember. Most of the car crash victims I saw in ERs were DOA, and most MI people were beyond saving. Death happens, often, as it must. That was a while ago, though.
There are several levels of it, so you can keep aspiring. There is always work too, part-time or full, or volunteer.