My poor dear ole' Sparky. He is aging. His bladder and digestion aren't what they used to be. He barks and barks to go outside. I take him outside and he just walks a block or two, pees, walks about a block more. Stops. Sniffs the same spot for a while. Stands there. Turns around and walks back home. 10 minutes later, he's barking at the door to do the same thing. What am I to do?