I think you need to push him for some specifics. Forget how much fuel came out it is irrelevent, there was enough to stop the engine turning over. The only way this can happen one one cylinder is if there is a fault in the injector or a computer malfunction causing the injector to open while the engine is not turning over. i dont care how big a injector is i cant see it spraying enough fuel to fill a cylinder to the point of locking while a engine is being cranked!
First change your oil! i have seen a few cylinders lock with fuel over the years and it has always contaminated the oil.
Second start from the beginning and check your engine for damage, ie comp test (on all cylinders) and a leak down test to compare all the cylinders together. If these come back at a acceptable level then i would work on the theory of no damage done and get on with life. Tune up, modify do what ever you want!
Obviously you will never be 100% sure but if there is no proof of damage then be positive.