Who pays repair of water damage done to lower unit,caused by uppper unit's water-to-air A/c pipes becoming disconnected? unit in

Water-to-air A/c unit is owned by owner, located in A/c room in his Condo unit.PVC pipes became unglued, water bursting, causing extensive damage to lower unit, as well as his. He feels it's a condo insurance expense to repair damage when it is clearly the same as if his water heater burst. Condo maintains well/pump system that brings water to all units, but this is HIS A/C within his unit where pipes detached.( Pump system is fine, servicing all units) This type of system was popular in years past, but is not the norm now, where you have compressors outside, on roofs of condos, etc. They are a single unit all self-contained. Thank you for advice.