Hello, I help to foster cats and am quite knowledgable overall in cat health.
I would get him to a vet's ASAP. He needs to be properly vaccinated (it looks like he has never gotten a vaccination in his life), neutered (so he doesn't feel the need to wander and contribute to the overpopulation of cats in your area), and can get tested for Feline Leukemia, and Feline Distemper. Both of these diseases are lethal and the cat needs to be tested for so that the cat in question doesn't die a prolonged and painful death. He also probably needs antibiotic ointment for his eyes, as he looks to have a severe case of upper respiratory disease.
You're on a great start, but he really needs some proper veterinary care.
I can help you if you live in the North Carolina/South Carolina area as I volunteer for an organization that takes in animals like Marmalade, fixes them up and adopts them out to good homes. PM me if you are interested and live in either of these states.