Give him the price of ripping out the drywall to add another IR wire from each A-bus keypad back to the head end. Maybe he will abandon the idea of controlling a zone volume from another area of the house. Hold your head up high and say "no". It is really a bad idea to control volume from an area you are NOT standing in. Let me adjust that statement; Do not try this without preset level capability.
I may be schizophrenic, but at least I have each other.