Thanks for the prayers and positive thoughts, everyone!
He had to be transported to a different facility (a specialist) as he was continuing to bleed from his nostril. Xrays showed that he crushed his eye socket and part of his nasal passage. Luckily the eye still has full movement, and he is seeing out of it. There is a huge amount of swelling & liquid behind the eye, so he has to stay at the specialist's for at least 5 days while they continue to treat the injured eye. They said that surgery wouldn't be necessary unless I desired it for cosmetic purposes. I said, "NO!!" The damage to his skull will be permanent, so he'll be slightly dented for the rest of his life.
He is 14 years old, and has already gone through one coffin bone injury, and a suspensory tendon injury. For me, this is the sign from the universe that it's time for him to retire, even though he is still physically fit & capable. He has given me so much of himself over the past 9 years, so now it's my turn to give back to him. He can be my pasture puff (ok, my second pasture puff - my daughter's horse is retired pasture puff #1) and I will be chief treat feeder for his remaining years.
Both of the other horses are very unsettled and anxious now, esp. with Courage gone. Whatever spooked him, has left it's impression in their minds too. We're out in the country, so we have coyotes, foxes, raccoons, etc. The barn hasn't been built yet, so they are in a 3 sided shed that had been framed into 3 large stalls. Very well built, and I thought it was very safe. I'm betting that a raccoon or something got into the stall with him and terrified him. The chicken coop is on the side of the barn, so various predators cruise past there on a regular basis. Panama, my white Andalusian, was especially clingy and needy today - very unlike him.