jamming it into park would cause the engine to rotate and skip past the rotation it was stuck at.
WTF!! Are you SERIOUS!? This guy is an idiot.
Putting it in park applies the parking prawl, which is like a ratchet on a gear. What you did, or he told you to do, is like putting a stick in the front spokes of a bike thats going 10 MPH. I'm suprised you didn't break the parking prawl! I bet he thinks he can push start an automatic too......(without going 50 MPH ofcourse)
Second....how would turning the engine over with the trans (or any way for that matter) remove the freaken water from the engine!!!?!?!?! Its HYDROLOCKED. Which means the pistons CAN NOT move up because the water is in the way. FORCING it is what blew your engine.
The ONLY way you can clear out an engine that is hydrolocked to the point it doesn not turn over is to remove the plugs. THE ONLY WAY.
OMG....I know this guy is your friend...but what he told you to do, costed you your engine. Hate to say it...but thats the truth.
Trying to start it and flooring the gas......again, you're just putting an enormous amount of stress on the rods/pistons.
*Deep breath* and *Sigh*
I hope this friend doesn't do the swap for you...I know its free...but at this point, he should be buying you an engine.