answer:It would depend on the overall condition of the dog. Option 1 seems a bit off if the dog, since the dog is likely too old to overcome it. Option 2 and 3 can be combined. I would likely go for option 2 and see if the dog still keeps on enjoying life. (that is… Lives life as a dog, doing dog things, etc.) If that doesnt work well, one can still go foroption 3. You have to keep an eye on the dog and as his owner you’ll ‘know’ whether he is still better off alive, or not. In case you do need to euthanize him, ideally the vet would come to your house. Then he (the dog) can go in the peace and comfort of the place where feels most at ease. In general, your dog is a strong social animal that will take his cues from you. Stay with him and comfort him.