In theory, no it shouldnt all fall in the well, the pump is at the bottom and there
should be a sucker rod( the rod that moves the pump) that runs all the way to the handle. The piston is probly made of leather seals and will not function and may possibly be seized. I would try to pull the hole thing up pipe and all, might be a chore to do yourself, but at that point you can estimate the water in the hole and the condition of the all the pumps working parts. You can test the depth to the surface of the water with a spool of fishing line and a floating bobber, once you get slack in the line, mark it, pull it up and measure it. You can also judge the depth by using a weight of some sort, i might consider using a rock instead a fishing weight, as all those contain lead but I doubt it would hurt you really. If the pump can not be repaired, look up Simple pumps. I have one as my primary water source, its just a kick @ss modern day hand pump. Cheers!