Sugar water is for a quick pick me up energy burst for weak and stressed chicks. It is best to have a very short use period and then with drawn. Other than that is doesn't have any nutritional value. It is not some miracle cure. It is over used and often is bad advise.
Chicks that continue with...
The chick needs more than sugar water dribbled in its beak if it is going to have a fighting chance.
Since the yolk has not absorbed it needs good nutrients to help replace what is lost.
The weakness is not only from your having helped it hatch too early and the loss of what was in the yolk...