The photos make me cry... so glad your boy is doing better and so sad you lost your mare. What an ordeal.
Reminds me of a story about a friend of mine who had a pit bull that was well bred, family raised and obedience trained. She went to visit another friend of mine who had full sized horses and a foal. They think that the foal sniffed the dog and in an instant the dog jumped up and latched onto the foals nose and wouldn't let go. The foal was horribly mangled and died from the attack. The dog also turned on the mare and started tearing her up and when the owner of the horses tried to get the mare away from the dog, the dog turned on her and tore her arms up badly. She was 8 weeks out of work with her injuries...Her husband ended up shooting the dog to stop the attack and then afterward he suffered a heart attack from the stress. The foal was dead and the mare had to be put down because the mauling was so bad. The power this breed has when they are set off is frightening.
This is not a breed I could trust or ever own. Too much power, too much drive and even wounded, they don't stop.
About a year after this incident, another friend of mine got a call at work by a state trooper that her son had been badly mauled by his friends pit bull. If he had not been wearing strongly woven jeans, he might have lost his leg. This dog was also, family raised, good breeding and well behaved and trained and had also known my friends son since he was a pup. Not a dog you would expect would attack. I shared these stories because it can be breed related. These were nice well raised dogs that turned into nightmare attack dogs. It isn't all about who raises them, and where they come from. Plenty of incidences of nice dogs gone bad too.
I hope your baby continues to recover. He sure is a cutie. Take care and best wishes.