3 day-old kitten having serious issues...Help?

Well, the fact is that he probably wont live. The best thing you can do for him is take him into a veterinary hospital or humane society and drop him off. If you tell them your story they'll take him in their hands for you no questions asked. That's what i did with a dove i found. But you cant call and see if he's okay or not. He'll be in their hands. Also no charge. If he continues to be shunned then that'll will be his only option. Best wishes!