If he gets worse, you can also get him some Pedialyte. I'm sure the Nutri-cal and canned food will be enough for him now, but just in case he stops eating, Pedialyte helps.

The vet gave me the name of the pill that I got over the counter at the drug store that helps the kitties get over the URI faster. He said it had to run its course, but this pill made the cats tons better. I don't remember the exact name of it, something like L-lysine. I can check for sure when I get home in case you want to call your vet and ask about doing that.