Curd has a lot of vit C please give it regularly through out the year and caugh and cold frequency will reduce. Also for now go with what Lynette has advised... for hot water.

Warm water to drink. Do not give bath and send her out. Wear slippers. Oranges, lime add sufficient Vitamin C try to include in diet. Avoid curd, cucumber, guava, banana, milk after 6 pm.