I wasn't there, don't know the situation, but it obviously worked. I agree...a 56# selfbow isn't comparable to a 66# longbow, but a 66# longbow isn't comparable to 90+ pounds either. I've told countless people (when I was a dealer for custom bows) that a double lung with 40# is much better than a gut shot or miss with 100#. There's a breaking point for everyone, and it varies, but no about of poundage will turn a lousy shot into a good one. The deer doesn't care how far the arrow buries into the dirt once it passes through...but it does care if it's a double lung vs. a gut shot.
My point is simple. Don't try to shoot more than you can handle. Whitetails aren't tanks, and nobody will regret a double lung with 40#. Everyone will regret a gut shot or miss with 80#.