I could be wrong on this but I don't believe there is a required statute for MDs to render aid in such a situation. Even if there WAS I highly doubt it would be grounds for permanently suspending a medical license. Medical licenses are suspended due to incompetance, billing fraud, and sexual harassment of patients (among other things), but not because they failed to render aid to a person who was not under their care.
Conversely, there have been numerous lawsuits whereby a person HAS rendered aid and they get sued by the person they tried to help.
I can only imagine how the friends and family of this diver must feel. But a petition isn't the way to do it. Perhaps several letters to his state's medical board would be the way to go.