Are you still making electrolytes or have you bought some NutriDrench? Once he is drinking and eating some, the electrolytes can be stopped, especially if they are homemade. Even NutriDrench should only be given for a few days, or they may cause diarrhea. Stop the milk. Only a little plain yogurt or buttermilk daily for probiotics are okay, but they cannot process a lot of dairy. Water is good, feed with a lot of water is good, and to get more into him sprinkle any foods with a little water. Scrambled soft egg, canned cat food, wet feed, tuna are all good as long as his crop is working. I had a sick hen who did not drink water for 5 weeks, but she got watery feed, enough to keep her hydrated, so that she survived.
 
How old is he? Has he had coccidiosis before? Do you have a picture of the poop?