I worked at Vet clinic for 5 yrs while I was in college. We used alot of Winstrol V on older dogs, and even many of the older Tennessee Walking Horses. The Adequan usually seemed to work pretty well also. I don't think the Tramadol is a narcotic, as one person stated in their post, put it seems to be almost as effective as some of the milder opiates. Most Vets would charge you an arm and a leg for the Winstrol, so I would probably spend my money on the Adequan if money is an issue, if its not then it wouldn't hurt. But one of the things you might watch is it might cause him to gain weight, which would probably hurt his hips and joints more than the help you would get from the Winstrol I never saw any of the vets put any animals on Deca, put if you could talk one into it, you could bring the dog in for his injections every week or two, til the Vet trusted you that it was going to the dog and not to you. Then he might let you give it to him yourself.
About the HGH, and you might ask someone more knowledgeable like Ulter, or Macro, but the Human Growth Hormone is made to correspond to Human amino acids, that's why it 191 or 192AA. It might not make a difference as to whether it would work according to a dogs amino acid structure, but I would definitely would want to know he(your dog) was going to get some benefit from it before I subjected him to ED or EOD shots.
Hope you can find some help for him. It really sucks having to see a dog go through the last part of his life like that.
RFOM