Owning a car like that is so expensive they have little resale value. The upholstery should be relatively easy to restore but the older a car gets, the harder it is to find other spare parts from junkers.

Most of the mechanical parts have to be made custom from machinists who specialize in collectible cars. Sometimes a part breaks that no one has made in decades so you have to hire someone to locate old drawings or create them from scratch, pick the materials, figure out the QA process, and so on.

If he restores it, it probably will be.

Old doesn't necessarily equal expensive. In terms of actual drivable cars from that era, collectors would put a real premium on cars eligible for the Mille Miglia.