Robert from what I read there is no reason to think he will not recover. A good job by the vet. They are bullet proof when healthy. Who knows how he did it. Look for ways he could have fallen or got stuck somehow, maybe his head got caught and he shook free. When wild ones get noosed, caught, they thrash violently to get free, ear damage is the biggest concern.
keep him warm. Their ability to heal is impressive.
Stay positive

jf