My oldest setter has similar symptoms and need to include piddling in the house on occasion. It is likely his future will be similar to your dog's. His seems to be relatively slow moving but the changes in mental and physical being is noticeable. I originally had doubts of his making it to Christmas but now the timeline has swung to not making it to the spring.
Sorry to hear of this in your dog, hold on to the memories and do not hold your dog responsible for what comes. The great but also hardest part is knowing you can end his degeneration when the time comes.
