Tell him he now looks less like Homer Simpson and more like Antonio Banderas. No need to wave a white hankie when the cold season hits. Believe it or not, colds are most frequently transmitted by hands than by being close to someone with a cold. Train yourself to avoid touching your face whenever possible, and wash your hands more often when around someone with a cold. This goes for keeping household surfaces clean, too.
Cold viruses can live for an hour or more after a sneeze.
If someone in your home is sick, use the disinfectant spray a bit more than usual. The virus can be airborne to some degree, though is usually at its most potent in the first two or three days when virus-bearing droplets are most plentiful. Avoid standing close to people who are coughing and sneezing heavily, especially if they don't cover their mouth and nose. Being exposed to someone with a cold while on the bus or at the movies probably won't hurt you. But office buildings and airplanes are notorious germ factories, as air is recirculated and dries out your protective membranes to boot.