I'm sorry he didn't make it. It sounds like he was pretty far gone when he was found. It is really important that if he (or anyone) finds anymore they get them right to a wildlife rescue or a vet. Most vets will take injured wildlife and care for them.

It's important that you not feed a baby unless you have been taught to do so properly. I've raised several squirrels and other wildlife, I was taught by a woman who has been doing wildlife rescue for more than 30 years (I've been doing it for 5 years). I have seen so many die because other people feed them the wrong thing or the wrong way before bringing them to us.

I remember once being at my vet's office and one of the vet assistants took me back to see a baby dove that was brought in a short time before. The bird was in bad shape because a man thought he was helping an fed milk to the baby bird. The bird had to be euthanized.