Hi, Welcome to health care magic, Abdominal pain,gas trouble or bloating and diarrhea with vomiting could be due to acute gastroenteritis or acute cholecystitis etc but it needs to be evaluated further by clinical examination and various tests. If he is maintaining good diet habit ,then it is good but here we need to find out the actual cause. He should undergo routine blood count,electrolytes with clinical examination of abdomen or ultrasound of abdomen. He will require antibiotics (quinolones or cephalosporins or antiprotozoals etc.) with anti-emetics, antispasmodics and anti-inflammatories with prebiotics and probiotics. There might be a need of fluid and electrolyte balance in body. You must take him to the gastro physician for immediate treatment, Regards,