Brief Answer:
Uncontrolled hypertension

Detailed Answer:
Hello

Thanks for the query

Uncontrolled hypertension itself can cause dizziness and nausea. However in order to help you I need a few more details.

1. What medications is he on for hypertension?
2. When was the last time blood pressure was checked and how much was it ?
3. When does he feel the most dizzy, for example while painting, getting up from sleeping position, etc
4. Does he have chest pain as well

Please get back to me, I am awaiting your reply

Regards

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Brief Answer:
Postural drop

Detailed Answer:
Hello

Thanks for getting back with the details. Dizziness occurring when in upright position is most often because of postural hypotension. Postural hypotension is most often because of a weak heart, the other causes are dehydration and medications such a beta blockers and diuretics.
I strongly recommend that he get evaluated for his heart as soon as possible. His blood pressure is not under control and he will require antihypertensives

In the meantime I suggest you to
1. Make sure he is drinking enough water and he is not dehydrated. About 2-2.5 litres of water per day
2. When he stands up from sitting position it must be gradual and not sudden
3. Consumption of food must be limited to smaller meals than large meals. Let me have small meals several times a day rather than 3 large meals

I hope I was of help, if you have any further queries please get back to me

Regards

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