Upgrading sway bar brackets on a Jayco Precept with JRide Plus can provide better stability and reduce stress on mounting points, but it's not always necessary. The upgrade is most beneficial if you're experiencing bracket flex or have added significant weight to your RV.
For your family of 6 with mold concerns, I'd recommend a newer gas Class A (2015+) over an older diesel pusher to minimize mold risk while still getting the space you need. The health factor outweighs the noise/comfort advantages of diesel in your situation.
Jayco Precept wipers use Ford chassis system. Check fuse, switch, and motor. Common issues are motor failure and linkage binding.