Could you get your horse those plastic horse shoe things to make him more comfortable? That way he would be relatively OK, and the lady could see that he can walk just fine when his feet aren't butchered.
I've never used them myself, but I've heard good things about them. They're almost like shoes for people - instead of a bended iron bar, they literally wear a shoe. It's said to be great for horses with messed up feet.
This is the kind of thing I was talking about
. There's a lot online when you google "horse boot," too, including reviews. Hope that helps and that your horse feels a bit better soon. Stupid farriers...