why is my dads 05 f350 hard to start when it gets hot, you have to keep cranking it

When what gets hot, the weather, or the engine? The engine may need a tune up ( spark plugs and wires, air filter, and fuel filter). To see if it’s a fuel problem, use a spray called Starting Fluid from Advance Auto Parts. Spay into the black plastic intake tube going into the engine about a 2 second shot. You could pull a small hose from the tube to do this. If the truck starts more easily, tell a mechanic, or this place.