He does indeed look like a very nice horse. He is tolerating her wide spread downward bearing hands, which she is holding that way to encourage him to carry his head lower. This he is indeed doing with an unsteady head indicating his discomfort.
I know, I know, I sound snarky. As a reformed eventer turned DQ, I have learned that the desired head , and body carriage can be attained by proper hand carriage, because the problem your attempting to fix is in his body.
So, please, get yourself some instruction from a real dressage instructor, some one who loves teaching, and can explain the dynamics involved.
Heβs too nice to mess up.