Being on vacation at the moment, I dont have access to my blackjack library but it is my recollection that Julian Braun admitted an error in way he calculated the remaining neutral cards. This error slightly changed the advantage and/or win rates but certainly doesn't invalidate the entirety of the hi-lo count.
That was also just an aweful presentation. In addition to being a poor speaker, the presenter didn't pay himself on two winning hands, dealt out of sequence once and dealt cards on top of chips. ???? "Being a postal worker for 23 years" may not be the best way to begin any presentation. lol