I don't know which product out there will help to bring it back but I do know that just about every Southwestern car's interior that I've owned or ran across has been destroyed by SUNLIGHT. So to save it from anymore harm I would keep sunlight to a minimum by covering the car, storing it with little contact to the sun and maybe even consider tinted glass. All of my northern rust belt cars have great interiors but as expected RUSTED sheet metal.....would take replacing a dried up faded southwest interior over RUST any day of the week.
Maybe there are some products from Mother's, Maguire's, etc., that would work but I haven't found anything better than minimizing sunlight/UV. Check the products and go with the best UV protection type vinyl and leather care product.
MikeR
