I understand your concern.
Well as you describe,possible causes of such symptoms in his case may include Hypertension,Inner ear inflammation,Cervical spondylosis.
He can try some self care measures which provide him symptomatic relief.
Monitor his blood pressure.
Also hydrate himself with plenty of fluids.
Take OTC Motrin.
Also do gentle massage with muscle relaxant ointment and apply warm compresses with a heating pad on back of neck.
Steam inhalation can be tried in case he has clogged ears.
Take OTC Meclizine for dizziness.
If his symptoms get worse over the time then visit ER ASAP.
Let me know if you have any further query so we can discuss it thoroughly in every aspect.
Waiting for your response.
It’s my pleasure to continue this conversation until you satisfy.