My wife had that. Benign positional vertigo or loose rocks in the inner ear. She went to the doctor who performed something called, IIRC, the Epply maneuver which fixed it immediately. He even taught me to do it in case of recurrence. But that was many years and I would not try it now.
What part of that seems confusing to you?
Having this right now, went to the doctor today. Quick dizziness-ish spells for the past 3-4 weeks when moving my head occasionally, lasting half a second or less. Finally went to the doctor today, and he is confident it is allergies (ears have a lot of fluid, etc). No symptoms that I would have noticed on my own. Script for a nasal spray and an as needed pill for dizziness, and then Benadryl for a few days, with Zyrtec as well.
Perhaps the implication that “one to two weeks” is a faster recovery time than “seven to fourteen days.”
That’s the joke…
Oh, THAT’s what that whistling noise was…
Turn your head and woosh.
Ok, I got whooshed.
It’s a pretty standard issue joke used when telling someone they (or in my case their child) do not need an antibiotic prescribed and that in fact the antibiotic would be doing them no good. Usually it’s told as two days if we prescribe the medicine versus 48 hours if we do not … but an episode of BPPV (without the Epley maneuver successfully performed) is usually closer to two weeks to resolution so modified a little.
In any case the description: “It only occurs when I bend over or cock my head but when it happens the world spins” is very textbook. Doesn’t make it for sure so, he needs the exam to confirm, but pretty likely. A good doc may perform the Dix-Hallpike test during the visit to possibly confirm the diagnosis.
Interesting - I can reliably induce a sensation like going over the top of a roller coaster by tipping my head way back. No one has been concerned about it. My neurologist (I have MS) seems to think it’s a party trick. But the cure is to not do that - I don’t otherwise suffer from vertigo.
Having suffered from recurrent vertigo all my life, I got this joke immediately. 
That’s interesting because my sister has MS too. Her bout was a one time thing, though.