Thanks for providing more information.
I understand your worry about the episiode of falling down and vertigo.
As he has been diagnosed with fluid behind the ears so it can be a possible cause of his symptoms.
The Inner Ear is also responsible for maintaining balance, and that can explain an onset of his symptoms when he stands up from a sitting position causing imbalance and lack of equilibrium.
And as he has started Z pack and prednisone on Monday so it take 24-48 hours to start work.
So now he feels better on Wednesday.
Most likely he'll be fine after completing his medications.
He should also take proper rest and avoid strenuous physical activities which can cause overexertion.
As his legs feel weak,so i suggest you to give him plenty of fluids and Oral rehydration solution.
Check his body temperature for next 3 days to watch for low grade fever.
If he develops another episode of vertigo then consult his ENT specialist again.
Hope this helps.
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