Ran a trap line when I was a kid, and caught a lot of coon. Had three as pets, all bottle raised within about a week of being born.
One male became to aggressive when he reached sexual maturity, and was added to my fur take that fall. Another male was fine to handle, but had to be kept outside as he was way to destructive indoors. At about 5 years old, he wondered off into the woods one day, and never came back. A female I had became my mothers pet, and was as tame as any dog or cat. She was killed by a neighbors dog when about 2 years old. The only way to tame one is to bottle feed it when first born. By this time of year, they are to old.
Coon don't carry rabies for years, it effects them pretty quickly, like any animal exposed.
Leaving it for its mother to return, as you did, is the best course of action. Nature will run its course, one way or another.
Reminds me of a story. A trapping buddy of mine had a big boar coon named "Mask". Gentle as a puppy. He kept it in an outside run. One day, he was missing. Couple days later we are checking our trap line, and there is a big male in a trap. Looked just like Mask. Brett said "Mask" to it, and it rolled on its back, like Mask always did. "Thats Mask" he said, and started walking up to the coon. "I don't know" I said. Well, it wasnt Mask. Tore a good chunk out of Brett's right hand. "Thats not Mask" Brett yelled. No ****. We ended up cutting off the coons head, and having it checked by the state for rabies, while Brett had to have his hand sewed up. He still has the scars.
Larry