Oops...missed one thing. He's still breathing hard, mouth open just a little bit, eyes are open. He did reposition himself in his crate and turned around.
No mucus and warm legs are a good sign... I worry a lot when they start open mouth breathing if they have cool extremities and/or mucus. Can your friend post a video?
Christina took Black in this morning at 8:30 am for a follow up. The injury still looks pretty ugly, but he's still alive, stood up today to eat and drink and even walked around, albeit slowly, before returning to his cage. The vet is sure that something from the outside got to him, that it wasn't an injury from within. After a check of the run, there was a hole, so it does appear that something got to him, though it still seems so strange that they a) didn't kill him and b) didn't get to the others.
At this point, they are simply keeping on with the treatment - antibiotics and pain meds. I know that there was talk of a cone of shame, I'm not sure if they went that route or not, I forgot to ask.