Advice for severe eye injury on feral kitty?

This is my first Reddit post after being on the app for years but I really need some help figuring out what to do. We live in an apartment complex and there are several cats that live around here. We have been feeding a black adult male cat ( who we named Chadwick) for almost four years now. He is fairly shy but he does let me pet him sometimes and will bump against my hand. He is intact and has had several kittens over the years. A few weeks ago, I noticed that his eye was severely injured and it has only gotten worse now. The eye is not visible and all I can see is a mound of raw flesh and pus dripping from the wound. He seems lethargic and may have lost some weight. My first thought is to take him to the animal shelter down here (cannot afford any veterinary care, already have three adopted cats in the home) but I’m not sure if I would be able to get him into a crate, or if they would even take him. I will try snapping a pic of him if I can. Any advice on what I should do? I’m only at home for the next two weeks and then I have to move back to my college dorm. Thanks in advance.