Okay, guys Im back with a little update. After countless of hours of trying to figure out with what he's doing in the video starting at 3:38 and on and when he starts talking about this F dominant chord. My main question about this video is that in the video at 3:38 and on he starts talking about how he's playing a F dominant 9th chord. But what key could he be possibly be in? What I assume is that if that F dominant 9th is functioning as a V9 dominant chord, then there's a possibility that he may be in the key of Bb - I don't know for sure. I did here him say C minor chord as well, which is the ii chord in Bb. But my point is that he's not applying a typical F Mixolydian over that particular V9 dominant chord, which us musicians would often use in this case, but what he's playing is possibly a F Minor Blues scale over that particular chord. But who ever heard that applying a Minor Blues scale over maybe a V9 chord starting on the fifth scale degree of a key? We musicians would apply Mixolydian over that V9 functioning dominant chord. I really don't know how he gets away with it, but that scale adds a sense of funkiness over that chord.