Nah, he's just being disingenuous.
He's an eliminative materialist. That is, he believes that non-measureable states are not just not measureable, they literally don't exist. Hence his statements like this (Towards the end, 4.08)
If you can not tell me the empirical distinction between something that has free will and something that does not, then there simply is no distinction between those two states.
As such the problem isn't really free will at all, but the idea of anything not measureable whatsoever. Logic, for example. Theoretical mathematics. Whether someone has 'answered' the challenge. And so on.
If he really has never met anyone who is capable of meeting 'his' challenge, then he must have been extraordinarily selective in who he meets. Particularly since the challenge itself is a variation of the cognitive zombie thought experiment, which points out that there isn't any way to tell, based purely on observation and measurement, whether someone has free will or not. And the use of a time machine is a reference to the use of a time machine in free will thought experiments to identify whether the universe is determined or not, a necessary condition for some aspects of free will. So he knows enough about the philosophy to adopt an eliminative position and quote key arguments, but has never met anyone who can point out that he's not commenting on free will at all, but the existence of internal states? I find that hard to credit. Hence the disingenuous comment above.
But the real question raised by the video is not free will in particular, but whether it's reasonable to believe in anything you can't measure. So here's my challenge: Explain to me why it is reasonable to restrict human inquiry things that are measureable. And then I'll explain to you why the explanation you gave isn't measureable, and therefore doesn't exist. Fair?