Is it an exam pressure? A mere acidity?

I teach a 10 year old boy at my home who is in 6th std now, he has LEARNING DISABILITY. His exam has just started now. He gave his 1st paper yesterday. Few days back i asked him and his mother that does he take exam pressure or not and both answered me "No". I was suppose to take his class today morning but since morning itself he was having nausea, vomiting and dizziness. I wasn't aware of that but his mother still sent him to me. Upon asking she said he has got acidity but since exams are going on, please take his studies. After half and hour around he again vometted and had dizziness. I called his mother and asked her to take him home. While leaving from my place she said he always fall sick during exams. Now I don't know about the usual symptoms of his sickness when he generally falls sick during exams. I just want to ask is it because of exam anxiety or it could be a mere acidity?