We had to put our dog to sleep about two years ago. We got her from the Humane Society shelter and she was a senior pet. We saved her and she became part of our family. She had trouble with her back legs for quite a while. The vet said it was normal for an older dog. We gave her gluclosamine supplements and good dog food and that helped her a lot.
But then she started getting disoriented and sometimes would not recognize us. She also had occasional seizures. The vet said she was starting to have a form of dog dementia and for the seizures we could put her on medication that would affect her liver and with her age could end her life sooner. We decided against the medicine and she only had one more seizure that made her totally deaf and partially blind. She would be so loving and sweet, then act like she didn't know us, just like when adults get dementia. Also, her legs stopped working and she was getting stuck in the doggie door and behind open doors. We finally took her in. It was very sad.