I agree he appears to get little external rotation. If forearm straight back is 180 degrees, then I’d say he gets about 125-130 degrees:
However, the video appears to have a low frame rate so we may not be seeing everything.
After a second look, I no longer think the glove stabilizes too low. But it does still appear outside of his torso instead of in front of it. But I’d still like to see him work on leading with the front hip (Hershiser drill and cross-over drill) earlier in the delivery and then see what effect that has downstream in the delivery.