He's not the only who's coughing and complaining in our family just now. I have escaped the pestilence (so far! knock on wood!). I tell them all to force clear liquids, even in they're not thirsty, to get lots of sleep, and wash their hands before touching anything other people touch. At night, they use humidifiers and homemade cough syrup (it's worth clicking on that link just to see 3-year-old Ben!).
When I was growing up, Mom would have us take Vitamin C to help our immune systems. What's the modern equivalent? What do you give your people to boost their immunity in the season of lots of people inside sharing germs with each other?