Whew, quick thinking and staying cool in a crisis! Glad he was okay. He sounds a bit kamikazee!
One thing you mentioned about the lower water bottle not being reliable. Due to the issues he`s having with mobility, I would always make sure a ground floor water source was easily obtainable in case one evening he can`t muster the energy to climb and gets dehydrated. Even a shallow ceramic dish or water placed on a wooden platform in a corner for example would suffice if you have difficulty getting a water bottle to hang or stand down there, although water bottle holders can be made from plastic drinks bottles and weighed down with a stone inside or some decorative pebbles, like this one in the image:
Easy and reliable: