Sending prayers and good vibes your way, HAF and Chance! Just wow... what news...
I agree with getting a hoof specialist out there; either a very well schooled farrier or whatever the next step above that would be. If you do look into nerve blocks, my grandmother had a grade TWH mare in her late teens with suspected navicular, and their farrier recommended looking into blocking her. They actually did a preliminary sort of procedure where a vet essentially novocained the mare's foot to simulate the actual nerve block to see if it would help her at all. The mare didn't do very much better numbed up, so they opted to leave her nerves alone. Turned out she didn't have navicular anyway, so so much the better. Perhaps you can do the same kind of "trial run" if blocking does end up on the table.
Good luck, and hugs to both of you.
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown