Hello dear, The symptoms can be attributed to the persistence of infection in the Gastrointestinal tract as well as loss of electrolytes from the body due to vomiting. Management involves 1. Administration of lots of fluid especially Oral Rehydration Solution (ORS) to replenish the lost fluid & electrolytes 2. Antiemetic agents to control vomiting 3. If the infection is due to bacterial cause, then a course of anti biotic needs to be administered. So, it will be better to consult a Gastroenterologist for proper clinical examination. Investigation like Ultrasound scan of abdomen & Upper GI endoscopy will be helpful to detect any pathological cause for the same. Wishing your friend a good health. Take care