I would really like to hear the mechanics of this. Did he start in a first grade and then jumped one up every month?
He completed "years" 1-2 last June, 3-4 this January and 5-6 this June. Sciences-Mathematics variant.
I'd like to know the logistics behind this.
Ok, so he's bored and super smart and talented, but the usual thing in those cases is to look at putting them up a year. At what point does the school re-evaluate the kid every few months and decide to give him the proper grade tests and put him up a grade that quickly each time. Seems dodgy to me, and I can't see that happening that fast in a school here in Australia at least.
This kid is only a year older than Sagan (who's in year 2 and has another
10 years left). Sorry but I don't see how this is possible given the massive volume of stuff they have to learn these days. Who's teaching him a whole years worth of stuff in a few months? He'd have to have his own full time teacher that is doing some sort of specialised cramming course, you could not do this in ordinary classes, absolutely no way. I call bullshit on that he's learning it all properly that quickly.
And I'm also skeptical that the test are being done to the same standard. They develop new tests every year and very likely wouldn't had even had the year end tests ready at those point to give him?

Also,
A Belgian boy has graduated secondary school aged eight after completing six years' study in just a year and a half.
At that age he had 10 years of learning left, not 6 1/2, what's going on?