First tell me why a OWI which is two levels above a DM took a new diver to that depth? Isn't that the real question?
no, it's not
this isn't about the certification of the dive guide.
you found out his certification after this sad incident.
He could have been a local fisherman that knew the sites and didn't even get in the water.
this is about a 58 year old man that had decided prior to the dive (your words) that he was going to dive beyond his experience and certification (from whatever organisation that is) and was allowed to do so because there is no governing organisation that would stop this.
Now, he is DEAD.
What do we as Dive professionals do to ensure it doesn't happen again?