I'm sorry you are having trouble.
How is he doing?
Can you post some photos of the poop and your chick?
What dosage of Corid are you giving?
A chick that is suffering from a Coccidiosis overload would most likely be sleepy or lethargic. Some symptoms include going of feed, loss of balance, loose droppings with mucous or blood and having a hunched/puffed up appearance.
Do the best you can to encourage your chick to drink the Corid water. The Corid water can be used to make a wet mash out the chick starter as well.
Corid dosage is 1 1/2 teaspoons Corid powder per gallon or 2 teaspoons of 9.6% Corid liquid per gallon. Give for 5-7 days - make sure this is the ONLY water available during that time period. Mix a fresh batch at least once a day.