IMHO, there is no penalty. He dropped the ball in the area as near as possible to where he played his first shot. He had a downhill lie. You can’t play the second any nearer to the hole (under this option). He had to drop (you can’t place) a few yards behind the original shot or else it may have rolled closer to the hole (remember downhill lie). Once drop is made, the ball is in play where it lies, regardless whether it bounced forward or sideways. I think he gets away with it.
Sorry, he gets to drop twice and then place the ball.