You have a well with no foot valve and no screen, so the suction pipe is down in a casing. How big is the casing? Is it a pipe a couple of inches in diameter, or is it a large tile maybe 2 ft in diameter?
Or is your well just a pipe stuck down in the earth?
Draw a picture of it. The suction pipe is down there and over time sand has been getting into the casing. The well has probably filled up to the point where the sand is at the bottom of the suction pipe. Now you are getting sand into the suction pipe.
You need to get some kind of pump to clean the sand out of the well casing, down several feet below the suction pipe. Then put the suction pipe down the well with a screen, several feet above sand remaining in the well.