Blurred vision, Dizziness, Nausea, Hot Blushes and Pounding Heart.?

My father has coronary heart disease. This evening before dinner, he took his heart and blood pressure medicines. He had a large dinner containing white rice, coke and bread right after he drunk a cup of tea with sugar. He’s been told he’s prediabetic close to diabetic and after the dinner he experienced symptoms like blurring vision, lightheadness, nausea, hot face and his heart was beating a little faster which i reckon he got scared that’s why. Do you think the signs were due to his high blood sugar from drinking the rice, coke, bread and the tea or his blood preassure dropped due to the medicine and as he had a very physical day today which we all know excercises or movements reduce blood pressure. Or did he get hear attack… i don’t think that’s the case becuase he had no chest or shoulder pain or shortness of breath. He also suffers from depression and anxiety but i don’t think was the case today too.

Please let me know if it’s dangerous?