Junkenpoo, I just want to say that I think it's absolutely wonderful that you are looking out for this kitty. Even though he is a stray, he now depends on that food and he might not make it once everyone leaves. If he allows people to pet him and purrs, he shouldn't be too difficult to catch and transport to the shelter.
Usually it depends on the shelter. Some are deemed unadoptable, others are given a few weeks, then there are the no kill shelters. You could always call the shelter and follow up on him, or perhaps visit and see how he's doing.
Thank you for keeping us up to date!