Cars should always be stored with a completely full gas tank. An empty tank is a real big problem when sitting outside because condensation/water can form on the inside of the gas tank and gas lines, causing corrosion and fouling.
I would not say that storing ALL cars completely full of gas is a rule. Depends quite a bit on how long of storage, type of fuel system, etc. Either way, this doesn't solve the OP problem.
I would suggest checking the fuel pressure at the fuel rail and perhaps allowing some fuel to escape the rail into a glass for examination. Check for dirt, water, etc. You might be able to clear the fuel line of bad gas or crud enough for some clean gas to get through, then a shot or two of starter fluid and it might start up. Otherwise, you might need to pull the tank for cleaning and flush out the fuel lines. I normally like to try the easy way first as often it will work.