If he won't nurse put a small amount (3 to 5 cc) of straight Karo syrup on his tongue. If he swallows, that will provide him with some energy. Do that every 30 minutes.
If he begins to nurse, you can try the bottle again.
If he doesn't attempt to nurse, he will have to be given milk or fluids with electrolytes with an esophageal feeding tube into his stomach, or he will have to be given intravenous fluids.