I think it is slightly odd for her to be asking for our help on her horses lameness in horse health at the same time as continuing to ride it and compete it and then post a picture of him jumping in critique though??
But here goes...he is very flat over a fence and you seem to have been left behind his movement as if he had cat lept it almost? But this has all been said before.
I think he could do with practising bounces to see if you can get him to snap up more infront and follow his movement and holding him between hand and leg so that he doesnt make this flat shape. That way he will drop his head without doing his giraffe impression that you have mentioned (bless him)
He has the scope though, but just because he jumps big dont forget hes only four and wants to stay smaller until his growth is final, and all at its strongest!
All the best with him and i hope he is feeling better?!