Congrats Vet!! 
Now that I have said that I will add...... when you say you will "treat" his mange I hope you will be considering the whole dog and not just be suppressing his symptoms. 
I would like to only adopt rescue dogs in the future, but sadly I can't agree to most of the terms I have seen for adopting. 
I suppose I could lie and say I will poison and suppress the dogs health and feed inappropriate food. 
Yes, the whole dog needs to be treated. It looked like demodectic mange grossly---the erythema/red skin, the itching, the hair loss, the location of lesions. Demodex in an adult dog is something that needs to be treated as a "whole dog" because of the immune systems response associated with demodex---you often see it in rescue dogs who've been severely run down, starved, basically stressed. As the dogs get better, the mange will often times improve/resolve. I didn't treat the demodex a staffie rescue I had a few years back had as a puppy, she had tiny circles around her eyes and I only saw very, very limited numbers of mites on skin scrapes. It got better with time as she got healthier.
Just so you know Flower (
) My plan with this dog is to skin scrape him as soon as he's in my possession, identify the mites he's got and attempt to quantitate the numbers. If its sarcoptic mange, I will treat him. I do not want that to spread to my other dogs or myself. If its really low numbers of Demodex on multiple scrapes, I'm probably not doing anything. He needs a chance to get healthier first. If its moderate to high numbers of mites on multiple scrapes and he seems really uncomfortable after a good bath and cleaning, then I will run him through a course of treatment, primarily to alleviate his discomfort. The mite issue might resolve itself with time, but I don't want the dog to be itching himself crazy, self traumatizing himself and inducing possible skin infections as his body is getting put back together.
As far as rescues go..... as having run more than one for several years---oen for pitbulls and one for reptiles, I'll be the first to say, some of the rescues out there are flat out stupid silly with their rules and regulations. Others are very good. This dog isn't going through an "official rescue". Its more of a word of mouth type thing--which means it may still fall through.
I'll try to post up pictures once we get him.
