The 6:19 chord is a D and it does look like in that instance he's using his pinky with the ring on top for a little more stability.

For the 3rd fret notes of a barre chord I'll either use both my ring and pinky, one string each, or barre with my ring finger. I never barre with my pinky. I would just do whatever is most comfortable, or learn whichever would be more beneficial to you.