The video title says 'drop B', which afaik would be just lowering the 6th string from a standard tuning to B, but instead it looks like it's going from E standard down to B standard (lowering all strings by 5 semitones).
That would be pretty ridiculous with no truss adjustment, unless you just want to be turning tricks (which looks to be the case here) by using light strings and loosening the neck with enough bow on B standard so that you could chug an open chord without the guitar fretting, and then taking it up to E standard while not caring about more bow/higher strings, and then do the video in reverse.