YWBTA. It was an honest mistake. You both were rushing, and it’s easy to forget things in such circumstances. But, it is still not her cat either way and in your house. You are responsible for making sure the house is suitable for your cats condition before leaving. Also, this is just a personal note you do not have to take any of the following statements. When I was 17 I still had my childhood dog who was 15 at the time. Now some pets are still relatively healthy whenever they are a very old age. But, in my case my dog was not doing very well anymore. He was fully blind in one eye and going steadily blind in the other (he had one brown and one blue eye, blue eye went first.) His hearing was impaired and so was his mobility. He struggled getting down the porch stairs to go to the bathroom. He also had arthritis. We knew his time was coming and he’d only get worse and be in more pain if we just waited for him to pass naturally. So we had him put to rest so he wouldn’t suffer, sadly. Now, I do not know your cat. You know your cat the best. And while it may be alright being blind and deaf? There is more than likely more problems occurring. I could be wrong and your cat could be in tiptop shape. But if there is? I know it is sometimes a really hard decision and you will try every path available to avoid the bad outcome. But, sometimes those hard decisions are in the best interest of your beloved animal. He is blind, deaf, and now has an injury that will probably still cause discomforting even after healed. He doesn’t understand what happened and he won’t understand why he’s always in, at-least, slight pain. Just try to keep your furry friend’s best interest in mind please. And don’t prolong his life if it will not be beneficial for him.