I've also come to realize that my ideal situation would allow me to provide rehabilitative care for patients, probably in either inpatient or a skilled nursing facility, and then turn around and provide personal training services for those patients to sort of extend their journey from just "becoming functional" to "becoming fit" or progressing beyond the minimum.
In particular, I've recently been inspired by a friend who's been dealing with cancer, whose outlet has been exercise. It seems to me (and I have no actual basis for this, just speculation) that there are at least a few people who would find a structured exercise regimen, modified to accommodate any limitations brought on by their conditions, soothing, particularly in the face of a potentially terminal condition. It also seems like training with the right trainer (and by that I mean someone with whom you connect, not just someone who kicks your butt) would be a source of therapy for the individual as well. It could also be a relief for loved ones who may be learning to live with someone who's suddenly home all the time because they're not quite well enough to work, but aren't quite sick enough to sit still. Actually, I wonder if group ex for families living in places like the Ronald McDonald house is a thing? It seems like it'd be therapeutic for everyone to get their sweat on and get out of their heads for an hour a day/week, but maybe that's just me. It's maybe a very specific group of people, but I think providing that kind of physical and emotional support in a fitness environment really appeals to me.
I have no idea if that kind of setting/opportunity exists, or if it'd have to be something that I set up on my own (work by day at a hospital or SNF and by night have my own personal training business at a local gym or something). For now though, it's the goal in the back of my mind that's going to keep me getting up before the sun to intern at the gym, studying hard to pass exams, and reading up on joint structure and function just for the fun of it.