Hi C....
You can give him something NOW... If your kids are sick, usually try to dose them right before bed because it gets worse when they are sleeping. Then, check the bottle to see how far apart you can dose them, usually every four to six hours. If he's running a temp, check him in about four hours and wake him up for meds if he's running a fever. What kind of cold meds are you giving him? ONLY do it if he's acting different, uncomfortable, fussy, not if it's only a runny nose with no behavior change. Make sure you are getting meds for infants, not toddlers, it's more concentrated, dose according to weight, not age, and call the dr if you have ANY doubts. As far as liquids, if he's still wetting a few diapers through the day, he should be okay. Do not force him to eat if he doesn't want to, but the liquids are important however you can get them to do it. Pedialyte has popsicles now or even regular sugar free ones work. Some people swear by echinacea, although I have five kids and have tried it, it doesn't seem to do anything. But my other friend says it does... So maybe it will in some cases. They sell gummi echinacea by vitamins for the kids. Also, a multivitamin drop can help just as maintenance. Wash YOUR hands and his often, I would stay away from a totally germ free environment, germs help them build their immune system. Now...prepare for all different opinions! lol Good luck. My two year old has a runny nose, but he only gets meds right before bed unless he's running a fever earlier in the day. I am using tylenol melt aways.