Hi Ron. I am very sorry to hear of your loss.
Ron I am from Florida and have had many horses, big ones, hit the ground from sand colic. It's a killer and I lost horses from sand colic. Our vets always tube mineral oil more than one time usually, give banamine and then we walk, and trot, and lunge until we get poop.
Personally I do not go in for Metamucil only because no one really knows the exact dosage to give. I used it many years ago in Florida with no success but that doesn't mean it won't work for you.
I used Sand Clear and Sandblast. You have to follow the instructions to a T. Horses hate Sandblast at first and do not want to eat it. You cannot mix it with water or anything so it may sit in the bucket for days before they eat it out of desperation. You do an initial "flush" for 10 days with Sandblast, but once they eat it, they will eat it readily afterwards. If you use either product, divide the dosage by 1/3 or 1/4 for a mini size portion.
According to the University of Florida, they have studies now that show feeding soaked beet pulp helps rid the gut of sand. We are in a very bad drought here Ron and all my fields are dirt, not a drop of moisture in the ground. It's dusty and dry and horrible and the horses are coughing so I am wetting down the hay with the hose daily and feeding sloppy wet beet pulp for lunch. They think it's a treat and may gain weight from it. I don't care if they get fat, I do care if they colic.
If you go to Jeffers Equine you will find many other options there for Sand Colic remedies. Good luck and best wishes.