The draperies are likely ruined. Your formula may get rid of the odor, but will not remove the staining, and in fact that volume of liquid might create an even more obvious stain than already exists.
I was a dry cleaner before I was a carpet cleaner, and in all my years in "the plant" there was not much we could do with urine damaged silk.
While you might recommend a dry cleaner look at the problem, I do not recommend that you act as a subcontractor or as any sort of "go between".
Us dry cleaners (I will always consider myself to be one I guess) are notorious for not taking responsibility for anything we do. Should you be associated in any way with the restoration process, you could end up "holding the bag" if the draperies are damaged further by any of the dry cleaners restoration processes.
Simply put: Run away.