It looks to me like the original is a color print that is fading away due to improper processing or improper storage or a combination of the two. Also I suppose you could add some not very good scanning to the mix just to kind of finish it off.
As for fixing it, I will admit that I am a better photographer than a retoucher. If a customer brought me that, I would say to them that I would have to look at the original before I would give any kind of opinion about fixing it.
However in looking at what you have posted, the outlook is not good

But you never know about customers, I have quoted prices that where just out of this world and have had people say go ahead, its worth it to me. I always collect those in advance though.