The owners are just hanging on to him out of pride, now.
I agree that he is not going to come out of this. There is no way he is going to recover from an infected joint. Plus he has an infection in the other hind foot. He needs at least one good hind leg to stand on and at this point he doesn't have it. I will be surprised if he makes it thru the weekend. At some point you have to weigh the chance of survival against the suffering the animal is going through, and if he has a bone infection he is in a lot of pain.