Calipers aren't supposed to be a wear piece, that would double or triple your brake job cost in a hurry depending on what you have for a car.
I'd help change the pads if you like him and have the tools. Wouldn't touch the caliper though. Cracking open the line and having to rebleed them could cause bigger problems and potentially liability in something where to go wrong in the future.
Caliper for a ,97 i believe it was, mercury mystique was 100 bucks or so last time I had to do one, pads for my dodge one ton dually are like 50 or 60 last time I did them.
I've never actually seen them come with the pads. Always been a seperate kit (in my experience anyways).
Put brakes on a girlfriends friends mustang years ago, "It just started sqeeling". It was the dual pistons wearing on the vents cast into the rotor because the whole brake pad surface was goooone. "but it just started". She was cutie as hell. Nothing to relate here just reminded me of that!