Sorry, I missed that the dog was missing (I have to admit a difficulty reading these posts).
Anyway, there is little or nothing that can be done if an animal hides away to heal or die. You can look, and look, and look, and if you get lucky, you might find it, but, usually, they'll go a few blocks from their territory (somewhere that potential threats won't recognize as the territory of another animal. The last thing a sick dog wants is another dog finding it and challenging it for its territory). One of my cats (from when I still lived with my parents) had severe kidney problems, and was getting really sick. He ran off twice. Both times he was found blocks away. The second time, he was so dehydrated that the vet thought it would be a matter of a day or two before his kidneys just stopped working, yet he went on to live another year after that (with his kidneys working better than before).
So the best you can do is put up signs, check the humane society, vets, police, etc... to see if anyone has found him, and keep looking for the dog, but if he doesn't want to be found, it may just be impossible to find him.
If you find him, homemade food made out of some kind of lean meat is going to be the order of the day.
Try this recipe for him: (Found in
Dr. Pitcairn's Complete Guide to Natural Health for Cats and Dogs)
3 cups rolled oats
2 large eggs
1 lb lean beef heart, turkey, chicken, lean chuck, or lean hamburger
2,400 milligrams
calcium (or 4 1/2 teaspoons bonemeal or 1 1/3 teaspoons eggshell powder, which can be made by baking eggshells until they start to brown and then crushing the shells in a mortar and pestle)
1 Tablespoon Nutritional yeast
1/2 Tbsp lecithin granules
1/2 tsp kelp powder (I use ground nori for this.
spirulina would work, too)
1 Tbsp vegetable oil
5,000 IU vitamin A
100 IU vitamin E
10 milligrams iron (optional, but I'd go with it for an injured dog)
1/2 cup veggies (optional)
Bring 6 cups water to a boil, add the oats, cover, and turn down to simmer until they are soft, about 10 minutes. Remove from heat. Stir in the eggs and let them set a bit from the heat. Then stir in the remaining ingredients and serve.
Cooking meat to "done" is unnecessary for most dogs, as their stomachs are made to handle raw meats. Further, cooking destroys certain proteins that dog bodies need. Our bodies can fashion these proteins from their building blocks, but other animals need their food raw to get them.
For the short term, you can simply make a smaller batch of oats (or rice), eggs, and turkey (the highest protein of the meats I suggested), but if you plan to feed this to your dog in the long term, I suggest very strongly that you follow the entire recipe, as the vitamins, extra iron, calcium, and such would be gathered from bone marrow, organs, and other stuff not in the meat you get at the market.
Also for the short term, cooking the meat through would not be terrible for the dog, and may be necessary to get it used to eating whole foods.
No matter what you do, start out with little bits of food and work your way up, especially if the dog ends up being gone for a long time.
The recipe I gave is a high-protein growth recipe (will be good for a . If you find your dog, and if he ends up getting better, and if you decide you want to keep him on whole foods, send me a PM or post a request in the "Dogs" section, and I'll post a more normal dogfood recipe.
I've been feeding my cats mostly on a diet from this book since the spring, and they've been doing wonderfully. Less dander, more energy, no hairballs.
Lastly, I want to reiterate that it is not normal (at least in MN) for a vet to suggest tests before seeing the pet. That would be like you calling your doctor, saying your hip hurt, and the doctor suggesting X-Rays, and MRI, a CT, and a bone-density scan before taking a look at you and seeing the big bruise you've got from running into a door.
You may want to call around, let the vets know that you've got a dog who has been injured, and that you just want a physical examination. When you get there, they may want X-Rays, but those usually run around $60 up here (I'm sure there are price differences in different parts of the country). It still would be $100-200, but that's a far cry better than $1,000.