There are some excellent and very savvy farriers & trimmers on this forum who might be able to suggest some things to help your horse
If you can, take very clear full body shots of all four sides of the horse. This will help them see his angulation. He needs to be standing square (no legs resting at half mast:) If he has a huge fluffly tail, tie it up with a hay twine, as close to the bottom of the bone as you can get:)
Also in good light, take pics of all four hooves top and bottom, including side views and rear views. To do that, stand the horse on something level, like the barn floor, cement, a level dry dirt area (like under an over hang, or stand him on a piece of plywood if he will tolerate that.
Set the camera on the ground so its "eye" is level with the hooves.
It might take two people, unless he's really calm and will stand by himself for you
I sure wouldn't give up yet