In general, Vicks Vaporub on the chest and back with a t-shirt on. Humidify the air. Warm steam (can take them into the bathroom and run the shower) for about 15 min followed by cool air (bundle up and take outside for just a few minutes... 5 or so, this is best in the cool night air when it's a little more humid) - a cure given to me by a doc for croupy cough. Plenty to drink. Water, warm tea, juice... no milk. Encourage them to spit out what they cough up. Wash hands, wash hands, wash hands. Wash toys, blankies, pillow cases, door knobs, fingerprint trails with bleach water to avoid reinfecting. Clean toothbrushes in hot water and soak in alcohol for a bit to disinfect... or replace them if it's time.