please help

Hi there. Last night a big black cat came meowing to my door step so I brought him in out of the rain and gave him food/water/a cat bed. I've put up posters around the block and at the store, called shelters/vets, etc, and am trying to locate the owners (very friendly cat).

He has VERY runny eyes and his nose sounds a little congested. His hair is matted. He's not drinking much, and I gave him some tuna since he hasn't touched his regular food today (though yesterday night he ate it). What can I do for him? I will likely bring him to the vet tomorrow if I am able, but what can I do in the meantime? Thanks.

Start by putting him in a steamy bathroom to help decongest his nose. If you can safely do so, use a warm damp rag to wipe away some of the gunk. If he's not drinking, you can offer a little cat milk or lactose free milk, or chicken broth (make sure there are no onions). Foodwise, I would try canned food, and then heat it for a few seconds in the microwave--that will make the food smell a little more, which can help in a stuffed up kitty.