Hello, has he suffered from such episodes in the past too. Is his BP under control? Does he take his medicines regularly.
Next Steps
Needs to get an ECG n ECHO done. It does happen due to sun stroke as well but as he is diagnosed to have hypertension, it needs to be evaluated further.
Health Tips
Increase his intake of water. Eating n sleeping well n at proper times to be followed. Smoking or drinking if present need to be abstained from.