Beautiful kitty and I envy you for still having him at this point - but I have to say after reading his story that if you haven't done a blood test lately I highly recommend you do so. Some of his characteristics are similar to those of my Angel Beyli who had Chronic Renal Failure. If diagnosed, it is not a death sentence as there is medication such as Fortekor (Benazepril) and antacids, as well as SubQs that can help the cat live a happy life - it does not prolong suffering, it really helps them to be okay. Plus, at this point, as others have said, it would be much better to keep him inside so that you can monitor his urine (they tend to urinate alot more and this is a sign or how he is doing, IF he is diagnosed, or even if not - it is important to know at this point). Just a suggestion from one cat lover to another.