See his doctor. Flu causes fever and cough, and in babies can lead to pneumonia and dehydration. Controlling fever, and pushing fluids, are the main treatments. See your doctor if your baby is younger than 6 months; has fever > 101; has other medical problems like asthma; won't drink; or gets worse after getting better.
Fever control, fluids. The symptoms of the flu can range from mild to serious. If your baby has the flu, make sure he or she is taking fluids well and that you can control high fevers with appropriate doses of Acetaminophen or ibuprofen. Signs that indicate your baby is getting sicker include rapid breathing, decreased number of wet diapers (which could indicate dehydration), and decreased activity level.