Wow, that is so sad about the cat with one eye. I a bit nift that a rescue would encourage the euthanization
of that cat. Ive rescued lots of very sick cats and rarely do they not respond to medical care. Im sorry you had to go thru that.
Most cats acting like the one you described is a dumped abandoned cat that is starting to go feral to survive. My rule of thumb is if your cat ends up in my yard and is not spayed or neutered then Im going to get the cat trapped and s/n, vaccinated and ear tipped.
With the economy the way it is, a lot of people heartlessly dump their animals (this is happening to horses even!) You obviously have a big heart. I would trap this guy. after s/n and release then continue to feed him daily.
There are stickies at the top of the feral cat section with ideas for shelters, how to tame feral or semi feral kitties, etc.
Thanks for being such a kind soul. Feral, semi feral, abandoned outdoor cats are the least helped in the rescue community. You are making this cats life a bit easiier with your help.