Video's title is clickbait... skimming it, the guy figured out how to enrich Uranium, invented the use of lead additive in fuel and Ozone-destroying flourocarbons.
The video is interesting, well researched, and makes good points. I'm skeptical about some of the claims (is lead really responsible for lowering IQ and raising crime rates? It seems too convenient.), but I found it worth watching.
Yes, lead is definitely responsible for that. It causes brain damage in kids.
I don't doubt this, but "IQ" is such a loaded topic.
Maybe you should watch it instead of skimming, because your summary is incorrect. (The uranium enrichment was done by a different person than the other two things.)
There are many different ways of enriching uranium