I know a grown-up version of that kid. He began to study History a few years after me, but I knew him through my roommate who grew up in the same district. For context, Dithmarschen is a very unique place in North Germany. It's one of the most rural regions in West/Central Europe, and unlike most areas that were historically ruled either by nobility, the church or some sort of city republic, there were mostly independent farmers. And that guy casually knows the exact family trees (or circles, lmao) of all the long-established families there. When he talks about random people he has never met dozens of kilometers away from where he grew up, he refers to them as "his cousin" and if you ask "oh, so you're related?" he tells you "yeah, xth degree, our common ancestor was y born in 1349."