Before anyone puts any supportive shoes on a "foundered" horse, you really really really need to get X-RAYS.
IMO (and in the opinion of many serious horse vets) X-rays are waaay overused and overinterpreted in the horse world, but this is very definitely one case where you NEED them. You can't see exactly what the coffin bone has done without 'em. In fact the better farriers I know will not attempt corrective/supportive shoeing for laminitis *without* seeing xrays.
So, call the vet. In the meantime, NO MORE GRAIN AT ALL PERIOD WHATSOEVER, and NO GRASS PERIOD WHATSOEVER, the horse should be eating absolutely nothing other than good hay, and living in a very well-bedded stall or small pen, preferably with deep sand flooring but deep shavings is better than nothing. Presumably this is no longer an acute laminitis situation so I am not sure how much good play-doh would do, but duct-taping play-doh to the underside of the hoof (so the sole and frog are bearing weight via the play-doh) is still probably not a *bad* idea if your grandmother can effectively do it.
But, VET, as soon as possible. Really really!
(Note that I have seen farriers mis"diagnose" clubfoot-grown-longish as a result of founder -- so that is another reason to get a vet out)
Good luck, have fun,
Pat