Sounds like a possible head injury. Add a pinch of salt and baking soda to his cup of sugar water to level out his electrolytes. If he rallies, treat him with a capsule of vitamin e once a day for a week. It may also help.
It would help to describe in detail what his injuries are. He is also probably suffering from shock. Shock is the first thing to treat. Warm sugar water - one teaspoon to one cup water. If the injuries are from punctures, then an antibiotic is necessary. Other injuries, especially closed ones do...