93 Suburban wont start, acting like battery is dead

Try turning the engine over by hand, get socket that fits the bolt in the damper on the front of the engine and break over bar and see if it turns with that, if it turns then it is not seized, if you can't turn it that way cause it acts seized, then try taking out all of the spark plugs, then see if you can turn it, if now turns then it was hydro locked, possibly oil got into the intake and drained down while it was sitting getting repaired. You can clear this out by disabling the ignition coil and then see if the starter will now turn the engine over, crank it over at least 3 seconds to clear the hydro lock, check the plugs and if they look good put them back if they don't now would be a good time to replace them, clean up the excess oil and reconnect the coil and see if it fires up, just make sure you are out in the open cause it will smoke until it get is all the oil cleared out of the system. Hope this helps.