Improper engine break in.

Hey guys, I've been milling it around in my head for about a week. Long story short. I helped a friend rebuild a mild 350 chevy. (I need Mopar Baptized!) After we broke in the cam for the 30 minutes, I mentioned changing the oil. He insisted that it didn't need changed for at least 50 miles. I told him otherwise but he drove it anyway. We drove the truck around for about 50 miles and changed the oil using the zinc additive. I told him about the 500 miles of lightly driving to break in the rest of the engine and he agreed. Then he sends me a video of him doing burnouts and romping on it with just over a few hundred miles on a fresh built engine.:banghead: I told him to go easy on it for a while after I saw the videos. Anyway, my real question is, How much damage could actually have been done to his engine? I would assume his rings might suffer a little and some internals might have a harder time mating. Do you think it will live if he baby's it for the rest of the break in cycle? I don't know everything, I'm just curious to know some opinions or experiences.:prayer:
Do a proper cam break in, change oil and filter, adjust valves if need be.
Drive it like you stole it.