That's Interesting, I have only hit a deer in the front shoulder once. It was from ridiculously close range with a 180gr psp federal from my 30.06. Of all the animals I've killed, it is the one that ran the farthest. It seemed to be thrown around 180 degress by the impact, (I say seemed because I'm not sure if a ballistic impact has enough energy to actually do that, the deer might have jumped around so quick it only looked like the bullet threw it around) But regardless, it landed on its feet and took off running (on 3 legs), it went all the way across the clearing 50-70 yards and ran head long into the first tree on the other side of the clearing then fell motionless and 100% dead.
To this day I refer to it as "dead deer running" as it seemed to have no idea what it was doing, it just went straight into that tree and I'm convinced it was dead before it ran into it. As for the running on 3 legs part, the impact of the bullet caused the bullet to turn to fine powder and the shoulder blade was half turned to powder as well and the other half was in about 10 distinguishable chunks. The bullet did not penetrate the shoulder but the impact liquified everything behind the shoulder to the point that all I did was open the deer up, pull out the pounch and everything else, which usually requires cutting and pulling, just ran out onto the ground...Nasty damage. Most meat, save for that shoulder and a few ribs was salvageable though.
I just thought I would mention that, as it is my one story about a shoulder shot and I wouldn't have thought about shooting a deer there if I wanted a DRT impact.
Any idea what kind of bullet your friend uses...probably something that holds together better?