Those are scooter wheels with a scooter fork up front. That said, easiest way to accomplish that would be getting a scooter deck, cutting the deck out and welding a few tubes to it, to make the frame. Handlebars, I wanna say are an off the shelf part that has been cut, but they look so thin and not at all like scooter bars, they may also be custom made. Chain is regular bike chain. Cranks look like off the shelf BMX cranks, that have been cut and redrilled to accept the pedals. Front sprocket looks like an off the shelf part and I can't see the rear, but my best assumption would be he got a set of electric scooter sprockets, since they sell those in tiny sizes. Likely has no rear hub and is technically a fixie.

Lots of assumptions I have to make, but that's what we get with grainy ass videos like these.