So far all the answers you have received reflect an American point of view within American legal standards.
You live in Australia. There is a difference.
I suggest you go the Forum titled
Scuba-related Court cases and do a search using the name "Watson." You will find a host of threads discussing the legal obligations buddy's have for each other
under Australian laws.
As a quick summary, a man named Gabe Watson went diving on his honeymoon with his new wife, Tina. On their first dive of the trip, she had a problem, and he was unable to rescue her. There were accusations based on false reports that he murdered her, but later expert analysis of the true facts indicated that his attempt to save her was simply incompetent. Under the laws of most of the world, that would have been the end of it--he had no legal obligation to perform a competent rescue.
But this happened in Australia. I am not a lawyer, and I am trying to remember what I understood about the particular unusual law under which he was prosecuted, so I cannot explain in solid detail. In short, he ended up pleading guilty to manslaughter and spending a year in jail. Understand that there was no intent involved--his guilty plea was based on an admission of being an incompetent buddy, and the judge's sentencing statement made that clear.
So, I don't understand that law, but I suspect that your legal obligations as a buddy where you live are different from ours in the United States.