Acidity and dizyness. And is it risky?

Yesterday my father went with the chest ct scan to an MD doctor and the doctor said he had little infection in his lungs and gave him some medicine, like azetromicin 500 and few others which also had acidity medicine, he came back, had lunch, took the medicine and after sometime he immediately started having extreme acidity and after an hour he felt extreme dizzy and became unconscious and sweaty. We took him to hospital and all the reports, blood, ecg bp and everything was normal. The doctor just gave him acidity injection and told us to go home. But since after that, when he eats even something very light he is feeling bloated and acidic. What can be the reason, please can anyone tell me please🙏? And is it risky?