Oh FFS. While O'Neill acknowledges the rabbit holes his mind went down, there's no neat conclusion precisely because he doesn't make any claims he can't back up with documents and on-the-record statements. Unfortunately, too many documents were destroyed and too many people are dead or unwilling to talk to put a nice bow on the whole thing. That said, remember, the book implicates numerous prominent people, many of whom are still alive, in serious crimes, including perjury in a capital case, and yet precisely no one has sued O'Neill or Little Brown for defamation.
Now, if we want engage in speculation: the HAFMC, which had been operating for over 50 years, closed in July 2019 barely a month after the book was released. Make of that what you will.