I would recommend changing the oil and filter, replacing the fuel in the tank and replace the fuel filter and drain all old gas from the tank, fuel line and throttle body. Make sure all fluids are full. Then see if it will start. Double check wiring under the hood if the vehicle has been parked where mice can get to it. Also, check the air filter for mouse nests.
If it doesn't start, check for fuel pressure and make sure there is spark to the plugs.