The brain damage/neurology studies he references have been a particular interest of mine for a long time. I highly recommend all the books by
V. S. Ramachandran if you want to read about more cool stuff like this in a very accessible way.
That being said, I think a lot of these phenomena actually make a stronger case for free will, in an indirect way. Take the woman mentioned in the video, who found her left and right hands physically fighting over healthy vs. junk food at the store after her corpus callosum was severed. On the one hand (nyuck nyuck), yes, she is now a living example of the fact that we have conflicting motivations in our subconscious, and that parts of our brain do stuff all the time without us ever knowing about it. On the other [redacted], she is
also proof that, in an undamaged and fully-functional brain, one side or the other--the healthy urge or the junk urge--does win on a daily basis without resorting to slap fights. Something in our brain, a "referee" portion if you will, oversees both urges and chooses a winner--and then, yes, the "interpreter part" of the brain separately justifies that victory after the fact. The key is to become aware of this interpreter function, and try to extend our referee function--our free will--to bypass it.
So for example, in the video, he talks about eating* the healthy leftovers vs. making the excuse to go to Wendy's because it's right next to Lowe's where he
totally needs to look at those paint swatches--and he says, rightly, that on some level we know we're bullshitting ourselves. Because of course we are. The question is, does your referee function live in denial and accept the interpreter function, or does it acknowledge the bullshitting? His larger point is that lower-level bullshitting is happening all the time that we can't recognize, but the first step to recognizing lower-level bullshitting is to choose to reject the less subtle bullshitting. The crucial thing here is that you don't actually have to make the choice to eat the healthy leftovers: you just have to admit to yourself that you want to eat the Wendy's and that's why you're eating the Wendy's. Owning the choice is more important in the long run than making the "right" one.
That's what free will is, and the more you own your choices and the genuine reasoning behind them, the more of it you have.
*And it is
super worth exploring why so many of our studies, go-to examples, and subconscious urges center around food, by the way...