First check with local upholstery shops to get recovering quotes. You might be surprised (in either direction). Then try shops further afield. Some places are just danged pricey, while others are fairly reasonable. There is nothing difficult about recovering RV furnishings, and in fact you can disassemble the sofa and take it to the shop to save some bucks. They typically come out easily, and also break down into 3-5 pieces. Just simple nuts & bolts.
My advice is to make Momma happy first. Makes the mechanical repairs go much smoother.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL