I have found that the low starch/sugar diet is the right start. I had a mustang that ate too rich a food, and had laminitis too. I feed only Chaffhaye now, it is great! Proper Barefoot Trimming is your next step. I have also heard, but not tried putting about 4 to 6 inches of pea gravel in the floor of the stall. Not only does it drain well, but the itty bitty size of the rounded gravel helps them to rotate their feet as they step around in there, and doesn’t get caught in the frogs. The more walking they do, the better. Pretty soon the floor of their hoofs will raise up into the concave form it should have, and your horse will be better. Good luck, and yes, it can take several months to fix, but sounds like you are well on your way.