How would you know?
You can tell by how rarely he audibles away from plays that will be bad because of the defense. If the play you’ve got called is a run to the near weak side and you see the weak side LB or safety creeping to the line you know they’re blitzing right at your run and your RB is doomed. And teams have an easy audible that says to reverse it, same play but strong side o-line block accordingly, even when coaches don’t trust their QB enough to give him a full rack of audibles they have that one. But you don’t see Tebow moving them out of the play, you can see his opponent showing blitz and Tebow not making any change and the run goes right into it.
Really we don’t see him doing much of anything at the line. And that’s re-enforced by them putting in an option offense, option offenses are basically post snap reads. They’re moving decisions that at the pro-level are generally made earlier to later.
The good news for him is the Broncos got a pretty cush schedule down the stretch. They got nothing but bad teams or hot and cold teams down the stretch. 3-3 is a gimme, 4-2 highly achievable. That puts them in the playoffs. Which either makes him solid trade bait, or gives them an off season to teach him some more. He’s a good kid, hard not to root for him, but he can be kind of painful to watch. Hopefully he’ll just get better.