The rear foot and leg does almost nothing in the golf swing. It's extended, so it can't "push." If you look at just about any good golf swing, the trail leg regains flex early in the downswing. The opposite of "pushing."
The core can move your hips forward a bit. Maybe your glutes (though probably not because, again, you're regaining flexion)… So, not a fan of this video. It's not what actually happens in the golf swing.