We don't know what the cave diver friend (Brooks) loaned and we don't know whether the loaner stuff was still on loan. It sounds like it might have been loaned exactly with the advice of taking a cave course and the intent that Spivey practise to do exactly that.
I would suspect most of us have borrowed gear to learn how to use it as part of preparing for a class. I know I borrowed the first stage bottle, reel and doubles I ever used. I didn't take them to depths or conditions beyond my training and I suspect that very, very few pre-course or pre-purchase borrowers ever do.
We don't know for a fact that the lending in this case was intended to be anything different.
I can also picture that if gear was loaned in good faith for appropriate practise before taking a class, having later realized what was actually going going on, a lender might find that getting his gear back from a bullhead like this might not be so easily done.
This friend might indeed have knowingly and repeated aided these misadventures, but we don't know that. Esp. since this friend's name has made it into the papers it would be best to not jump to conclusions.