Urgent: Badly injured duck in need of help

[MaryOfExeter]

My brother called this morning and said something got their ducks through their cage, killing all but one. He said the surviving duck had something wrong with its eye.

Well, we just got back a little while ago with my newest addition to the family. I was SO mad when I got there. The ducklings (who are in their 'teen' stage) were crammed into an all wire cage at night (thankfully they were free range in the day and had lots of room!). The cage was set up off the ground about 4-5 feet by a wooden poole - making it easy for any cat, coon, or possum to climb up and nibble away at their feet!

This duck is in pretty bad shape. Something wrong with its eye?? How about the whole side of his face is eaten away!

Anyway, when we got there that side of the face was covered in flies. When I blew them away, I found a mound of fly eggs (I'm guessing?) under the eye, below the beak, and a mass in the duck's crest. The wing is also a bit roughed up, but not any open wounds that I can see, just a little baldness and irritation.
When I got him home, I instantly gave him a lukewarm bath with some dish soap to get some of the blood out of the feathers and clean up the wounds. I did my best to disinfect the wounds with peroxide. I'm hoping that and the soap killed the bugs, and made it harder for any future maggots to feed on the bird (since the peroxide kills dead material). I did all of this outside, so by the time I was done washing him, the neosporin was nice and warm, so all his injuries now have a nice coat of that on it. Now that he's all greased up, the flies won't bother him. He's out in the sun drying with some ACV water and chick feed.

I gave him a 1/4 of a Penicillin pill (called Bird-Pen). That's how much you're supposed to give pigeons. I've given the same amount to chickens and ducks before, so I figured it'd be a safe dose to help fight infection. Other than Terramycin, it's the only antibiotic I have on hand. I was hoping you guys could give me some extra advice, or maybe suggestions for better medication and whatnot. The poor little guy HAS to be in pain; I feel so bad for him Is there anything else I can do to make this as pleasant as possible? Later I plan on bringing him inside in a rabbit cage. I'll make sure he's nice and warm. I'm afraid to keep him outside (like I'm sure my parents would rather me do ) because the flies are out REALLY bad this year, and I've dealt with maggot infested ducks before....YUCK!

I'll try to get some pictures soon. I've already starting calling him Tippy Jr. If he makes it okay, he's going to be one spoiled ducky here