He's gotta loosen up his feet faster, but I understand his inexperience. If I were him, I'd ask to get punched in the gut prior to the game. Once he gets moving (his feet), he's a different QB. Early on, those feet were in cement. He missed a couple throws that should have been 6. You can tell simply by how and when he climbs the pocket. Pure ladder drills this spring and summer - hopefully under a new coaching staff and culture.
I would have still put the ball in his hands on that late 3rd and short. Let him hit a quick route in the middle of the field (out of an empty set) OR run it. He's a gamer. Leave the ball in his hands.