Hi,
I would start by changing out the brake fluid, and get the Ford 24,000 GVWR motorhome brake fluid, it has the very highest 'wet' boiling point of any brake fluid.
IF the brakes feel 'mushy' it can be that there is to much moisture in the brake fluid, and it sometimes boils a little bit, and steam is compressible, not brake fluid. So once the moisture boils inside the brake fluid, then it becomes steam that is compressible. New brake fluid solves this problem.
With 30,000 miles on the truck, it might be time for new and thicker brake pads. They are not that expensive (less than a tank of fuel cost - say less than $75 per axle) if you or a buddy can change them in your driveway.
You can check with Napa auto parts, and they might have a stronger brake pad. However the 'stronger' brake pads are likely to warm the rotors more, and wear away more rotor material between brake pad changes. So it is a trade off. Ford designed the brake pads, and probably spent $1,000,000 testing various brake pad materials, checking them out on the race track and Arizona test track. Hot braking tests, and at 45,000 miles measuring the rotors to see how much wear is on them.
Why change the well engineered Ford product? It is not like the Ford brake pads are a known problem. Stronger than stock parts will wear out the rotors quicker.
Good luck!
Fred.