I’ve put some neosporin on his eye but not consistently as the liquid was super sticky on his eye and I didn’t know if that was ok. He’s been drinking a decent amount of water today but since I’ve been giving him electrolytes daily, I switched to fresh water today and he doesn’t seem to like it lol. Must be the molassesIf you have only done the eggs shells a few times, it should be perfectly fine. It is more consistent high levels of calcium that can be detrimental. Even female ducks can't have high levels of calcium till they start to lay eggs, which is around 28 weeks in Muscovy.
His eye may be producing more fluid out of it's tear duct to clean the eye. That's great that your are keeping up with the saline, it should help a lot keeping it cleaned out. You can put some Neosporin without pain med on it to help or get some terramycin, which is the best antibiotic for an eye injury.
That is good you were able to get more food in him. Just make sure he is drinking just as much.