That is amazing the hoof growth from those set of pictures, last year I had a neighbor's stallion jump his fence and then tore my fencing up to get to my mare and they got into a fight. He basically filet my mares leg down to her coronary band, with his long feet,the stallion was 8 never halter or lead broke they just stuck him in a pasture with poor fencing and no grass,it was sad conditions.
It took 6 months to heal my mare's leg and cuts on her thighs and even my gelding was jumped. Some people just should not own horses. I didn't even know there was a stallion up behind me in all that time.
I thought from the pictures that the vet did a great job of removing the proud flesh and the cast is a must or you'll end up with the wound being split open constantly by movement or knocking against obstacles and open to bacteria.
That area is a difficult area to heal to say the least..debriding would only start after it is well on it's way of healing over.
I would think it's time for that rancher to start checking and fixing fences don't cha think ?
Best to the horse always.