You check his uric acid, because it seems like cyclic 
vomiting.1.Follow hypouraturical diet-without chocolate,peas, rajma,spinach,tomato,market juices.
2.Give antiemetic-domperidon, ondansetron-1 ml 
3.Do correction of flora of intestine-take a probiotic- 
bifilac 1 caps 1 time 1 month
4. For normal absorbtion add enzimes 
You should exclude Wilson-Konovalov's disease-examine 24-hour urine excretion of copper,exine at ophtalmologist,do 
ultrasound of liver ,in the end-MRA of brain for exeption contain of copper in nuclei of brain.
 About allergy,it can happens if uric acid increase, give antiallergic-desloratadine1/2tab 1 time 7days and 
charcoal 1 tab for night 5days
All the best