Chick chairs aren't for long periods. They're used mainly to get a new chick upright to strengthen the legs.
You're over-medicating the chick. Nutri-drench is for short term treatment of a sick chicken. Too much can cause the very problem you're trying to resolve. And using the electrolytes for an extended period isn't good, either.
You probably have a failure-to-thrive chick (FTT). They can have underdeveloped organs and have trouble processing their calories efficiently. They don't grow. They fight to hold onto body heat so they need more heat. Wry neck manifests sometimes by the chick walking backward. The treatment is one vitamin E 400iu capsule each day until the chick recovers. Usually happens very quickly.
It may still be suffering a bit of hypothermia after it's tumble in the water. Give it a little warm sugar water. That will raise the glucose level and revive it.
Besides fermenting the feed, you can give the chick boiled egg and crumbled tofu.