He doesn't get anything right, because he's a crank conspiracy theorist who makes stuff up to sell books. For more, you may be interested in these previous threads:

https://www.reddit.com/r/AskHistorians/comments/4wzitm/is_graham_hancock_credible/

https://www.reddit.com/r/AskHistorians/comments/erjfaj/does_the_theories_of_graham_hancock_have/