Poor thing. It is so hard to watch our loved ones age. What you are describing sounds like Christy. For years, Christy used to lay in the front yard and greet the school kids. She was trained well and never stepped off of the property. Well after years of being the neighborhood lawn ornament, she started wandering away. We'd find her a few houses down looking confused. We had to start chaining her up. I think she lived another 4 years or so from when she first started showing signs.