Won't start?

you could have cracked head or block pouring water on hot engine

it overheated, you sat at idle and ran the a/c. you continued to do so, without airflow through the radiator except what the fan was pulling. you did not increase the fan speed by raising the idle.

so, it overheated. then you poured water OVER the engine.

simple , first, you need to diagnose the overheat. start with a new motorcraft thermostat. flush the cooling system. run tests for a head gasket problem. inspect the oil, pressure test the cooling system, remove the spark plugs, crank it over. note if coolant shoots out the spark plug holes.

next you need a book about automechanics and the vehicle owners manual. read them.

next check for spark, verify fuel.

you dont want to invest money till you know the extent of the damage you have done.

report back with info about what you found for the overheat.

do you think maybe sitting at idle , parked, running the a/c will put the cooling system under maximum stress?

since you overheated everything, now every part has been compromised, is weaker and libel to break or fail.

proceed carefully inspect for leaks now that the stress has been severe.

your no start may be failure of parts in the ignition system or fuel system. run tests and report