Hmmm… wonder if he was “known” to the FBI?
The supposed manifesto reads more like a set of directions made to somebody under hypnosis than an actual manifesto. And it really does not read like something written by a typical 18 year old, crazy or not.
It looks like the answer is probably yes. He threatened a school shooting last year, and was sent for psychiatric help.
https://www.dailymail.co.uk/news/article-10817615/Buffalo-white-supremacist-shot-dead-ten-threatened-shoot-classmate-graduation.html