I had a Wahoo grabed by a 4m Tiger shark in Vanuatu years ago ( Ididnt see it but the guys from the bridge called it).
This thing ran off 400-500m of 24kg straight down and broke me off before I could get into the harness.
So after an eternity winding the line back on I come up with a stainless 14/0 hook bitten clean in half- still have the hook.
It amazed me the power those things must have in their jaws. So in answer to your question a good size shark has the ability to go through a 7/0 hook with ease. Of coarse how the hook is lodged in the jaws etc. would play a big part. I think mine and probably your mates experience was a fairly unusual set of circumstances as I dont think it happens often.