My D-800 may be dead

This is exactly how I see it.

You took the risk, you brought the camera, you caused your camera to be damaged by putting it in the situation you did.  It's not your friends fault, and if you want blame to be placed it has to be placed on yourself.  If you got mad at your friend, I'm afraid you were wrong to do this.

I'm sorry you had to experience this painful lesson, but hope that you get your camera repaired soon!  I'm sure in a few weeks/months you can smile about it, but don't waste your time getting angry about it in the mean time