Sounds like something a Pete Ramey type proper trim and booting for pain relief would help with or cure.
I've seen numerous horses nerves who have continued to work. Also the use of equipak as a pad can put greater pressure on the solar surface if applied equal or convex of the ground plane of the shoe. Direct pressure on a pad like this adds density to the sole but transfer of pressure to an acutely thin or short sole with be direct and u advisable. In a case like that a firm pad over the sole but under a shoe can protect the sole from ground contact. Underneath the pad a softer product like equipak Soft could be used or a natural packing like magic cushion which has more toughening quality to the exterior of the sole. If a carrier continues to strip the sole out of a horse like this or over trim in general. The rest is academic