Edit: Here’s a link to what is most likely the real manifesto: https://www.kenklippenstein.com/p/luigis-manifesto

Ken Klippenstein is a very reliable journalist and this version of the manifesto contains the snippets that have been released by law enforcement. Also, considering the thing was hand-written, that very long version involving his mom is dubious. (And there’s not any good evidence that his mom is in anything besides decent/good health)