Severe second founder just 3 months after initial, prognosis?

Then I think you need either a half pour in pad setup or some kind of modified frog support pad that will allow proper support under the frog so the foot can try to recover. Frog support pads have a wedge on the bottom of them under the frog, again, so the pad contacts the ground. These tend to be harder (than leather), plastic pads. But they still aren’t as good as Equipak at promoting sole growth. And you may have to modify them such that the pad isn’t under the tip of the coffin bone (some have cutouts, some don’t). All that considered, a half pour of Equipak would be a lot easier. You can buy the materials yourself if your farrier doesn’t stock them. Just note that once you open one of the tubes, you will only get one shoeing out of the stuff. It will start to harden, so you’d need one tube each shoeing even if you don’t use it all. It wouldn’t hurt, though, to put it in a full pour on the other foot if thin soles are an overall problem for this horse. It honestly doesn’t sound like the current setup is going to do what you need to stop the rotation while the front of the hoof grows out.