[pokeymcsnatch]

So, you're definitely right- go to someone with actual medical training first. But a physical therapist's job is to get people back to basic functioning. From there, a good fitness instructor can help a person with stretching, light exercise and strength training, and stuff like posture/positioning and meal planning to maintain and improve on the initial work put in with the PT. A fitness instructor/coach is a fraction of the cost of a PT, and if you maintain a good relationship, you can just kind if drop in for guidance as needed vs going to weekly dedicated sessions.

But yeah, they can be literally anyone. A good one understands simple (bio)machines and pays close attention to how a body moves AND is a good teacher.

Edit: "A PT will get you to functional, a fitness instructor will get you to capable"