I'm not trying to stir the pot, but if hubby is knowledgeable and capable enough to change brake pads on a car he can do brake calipers on an RV. It's mostly the same task except he needs to remove a brake line and bleed the brakes to change a caliper.
Hydraulic jacks take essentially the same force to raise the vehicle and it's even harder to get stooped over into the wheel well in a car as opposed to a truck.
Also, if you change the calipers, you're almost changed out all the brake fluid during it. Use a syringe and suck the brake fluid out of the reservoir to about 1/8 inch above the bottom and then about 10 bucks in brake fluid will refill the entire front brake system with fresh fluid (IE: what they are calling a "flush").
Brake fluid is hygroscopic, it pulls water right out of the air. The master is not as "sealed" as many seem to think. This creates issues in the brake system such as internal rusting on steel components (but not only rusting, as I will expand on in the next paragraph). Combined with seals that break down in the system over time it eventually becomes "contaminated".
However, in the greater scheme of things, all this usually does is lower the boiling point of the fluid. This can give you a soft pedal after heavy brake usage. IE: trailing brakes down a mountain pass, etc.
What happens is the water boils to steam under heavy braking. It;'s a very small quantity, but steam is compressable while brake fluid is not. This compressibility in the system (that is not supposed to be there) makes the pedal feel "spongy" when it happens. The brakes will still work, but it's a very unsettling feeling when it does it and you're halfway down a 6% mountain pass.....
Most of your other items seem kind of "sketchy". Roof's can be patched, do you really need AC (even so if it's working it's working), and if your rig has both 12v and shore power services available your converter is working.
It's also a little hard to understand spending 11g on an older rig because you want to save/don't have money, then dropping 4g into what could be interpreted as "want" items and then "balking" at spending money on safety items like brakes. Not trying to judge, it just doesn't seem very consistent with your stated situ.
Where do you live? There may be a few good Samaritans on the board who wouldn't mind giving you a hand. I know I would have no trouble popping down the road and hour or so to help someone change out brakes. It's a 30 min job for me (I've got just the "tiniest bit" of experience at it
), so no sweat off my back. I'm sure there's others out there that would feel the same way about it. Maybe close to you right now....
Good luck (sincerely) in making a new life elsewhere.