Wooowwww.....This would be a horse I would apply casting to to get him temporarily comfortable. You can get a box of 10 o ebay
for around 35 bucks shipped instead of 15 dollars a roll for the name brand equicast. If you can wrap vet wrap around a hoof, you can apply casting. There are tons of you tube videos on apply it. It should make him almost immediately comfortable. Id leave it on for 2 weeks or so and re access. Hope Patty can help you find someone competent. Yoy may see if the vet can give you anything to help the horses comfort during trimming so the farrier can really focus and get this done right.