Forklift truck brake shoes hardly ever wear out. Typically the wheel seals leak, as in your case, or the wheel cylinders leak. In either instance the fluid soaks int the shoes and they must be replaced.
It sounds like you should call a different dealer to perform the work. A brake job on this truck can be done on the road at your location. It really isn't very difficult. I also don't know hwy he is recommending turning the brake drums. I would only do that if some hardware broke and gouged the drums.
The cost to do a complete brake job on this truck shouldn't be more than six hour labor maximum plus travel time, mileage and parts.