Sugar water, a few drops every hour will do more to revive a sickly chick than anything. Have you tried it yet? If not, what are you waiting for?
If you have no syringe, wet a Q-tip in the sugar water and drip it on the side of the beak. The chick will suck it in. Keep doing it until the chick refuses to suck in any more. Do it again in an hour. Keep doing it every hour.
If you have no syringe, wet a Q-tip in the sugar water and drip it on the side of the beak. The chick will suck it in. Keep doing it until the chick refuses to suck in any more. Do it again in an hour. Keep doing it every hour.