There are plenty of qualifications to be had - from the RYA for example - but you don't have to take them, any more than you do for kayaking or riding a bike.
Or going out in a boat fishing, etc.
But I can't imagine a skipper of a boat like that being a complete novice.
It's obviously a racing class of some description, and it looks to be in some hot country, hence the casual dress style.
To be fair, it's not easy to control a boat of that sort in those conditions.
If it was me..... I wouldn't have a boat like that, and I wouldn't have a spinny up, and the crew would all have lifejackets or harnesses, and would certainly not be scattered all over the deck like a bunch of layabouts.
Maybe that's why I sail a Drascome Lugger single handed
Here's how to do it...
https://www.youtube.com/watch?v=iUC7lVnL31I