Just watched the new Netflix documentary on Flat-Earthers.
I recommend it. It's quite good, funny at times. Insightful, and often sympathetic to flat-earthers (not sympathetic to the claim that the earth is flat, but to the people), who it seems to me are filling a psychological need that all people have, which is to be part of a community, feel special, feel respected, and have a mission in life.
It occurred me that flat-earthers are a sort of smaller, much more harmless version of the alt-right. Only sort of: the alt-right is hateful and racist as well as delusional, and that's obviously an important distinction.
But still, it's an insight into how people can believe crazy things in the face of huge amounts of evidence. It's also an insight into how the internet, which on the one hand makes scientific knowledge much more available to anybody, also makes it much easier for groups of people to become convinced of crazy conspiracy theories. For flat-earthers it's the shape of the earth. For the alt-right, it's things like pizzagate, or the long-debunked "IQ science" purporting to prove that some races are inferior, etc.
And by taking flat-earthers as the subject, it allows the viewer to focus more on the psychological mystery of, basically: WTF, is this for real? If the subject were, say, climate deniers or creationists or anti-vaxxers or whatever, then I would get more tied up emotionally in the damage that the those beliefs are doing to the world. And even though flat-earthers are obviously part of the larger anti-science denialism, which is a huge problem (and a lot of flat earthers are creationists, anti-vaxxers, and climate deniers, of course), still the flat-earth belief in itself is enough of a total joke that I didn't harbor any animosity while watching, just curiosity.
To be honest, some flat-earthers seem like intelligent, decent human beings. Some are obvious whack-jobs, but not all. Some even go to the lengths of doing actual physical experiments to "prove" the earth is flat (spoiler alert: it's round). And they do a solid job of it, so good that their experiments show quite clearly that the earth is round, and it's kind of funny watching their reactions. Do they change their beliefs? No. Must have done something wrong in the experiment, let's try it again...
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The trailer teased that the Flat-Earthers pooled their money to buy a state-of-the-art $20,000 gyroscope. The tried to prove that Earth doesn't rotate. They found in multiple measurements that Earth does rotate, 360° in 24h.
Later, the cameraman was at a party, where he filmed from afar one Flat-Earther whispering to another that they have found that Earth rotates, but that they cannot possibly publish this, because it would cause an outcry in the community.
Or if there is, he doesn't work much or never leaves the midwest on any of his/her flights.
It would probably take too long to train one of them to fly, but there are probably enough of them good enough with the mathematics involved with circles that if you stick them on a boat, they could verify headings and course to make sure the crew sails them to where the edge is supposed to be. 
TlalocW
“Mad” Mike Hughes’ home-made rocket launches near Amboy, Calif., on Saturday, March 24, 2018. The self-taught rocket scientist who believes the Earth is flat propelled himself about 1,875 feet into the air before a hard-landing in the Mojave Desert that left him injured.
Mad” Mike Hughes is carried on a stretcher after his home-made rocket launched and returned to the ground near Amboy, Calif., on Saturday, March 24, 2018. The self-taught rocket scientist who believes the Earth is flat propelled himself about 1,875 feet into the air before a hard-landing in the Mojave Desert that left him injured. Hughes tells The Associated Press that he injured his back but is otherwise fine after Saturday’s launch.
My son is so much like yours. He was identified as gifted very early in his life (around 3rd grade), was always interested in anything and everything, especially math and science. He's now what I like to call a "rocket scientist" at NASA. That's not his official title of course, but what mother doesn't want to say her child's a rocket scientist? 
I don't even pretend to know what he actually does. But like you, whenever I have a question about something I ask him and he too is very, very good at explaining things on a level and in terms "regular" people can understand. He of course despises any people who think the moon landing was faked.
You and I are very lucky to have such interesting sons. My son was quite a challenge for me as a mother because he was always wanting to try anything and everything that interested him, so I encouraged that. But I also had to balance keeping him humble and teach him how to interact with all kinds of people. I'm most proud that I succeeded in that. I've never met a more empathetic man who is kind, polite, a liberal Democrat who cares about everyone who's less fortunate than he.
The Alt Right are scary, dangerous, and delusional. The Flat Earthers are just delusional. 