This was definately an all round bad situation!
The reports I saw of this did not say anything about the person being treated by a non medical crew member; stating it was a ship's nurse. That would be ABSURD if true.
In the afternoon the ill passenger did see a Dr. and a lot would depend on how they presented at the time.
On the other hand everyone has to know that ship's medical centers are not equipped to handle truly serious medical situations. They don't have the equipment available to even do thourough testing.
If they had discovered the real problem earlier, considering their location, I'm not sure what their other options would have been. They are reliant on their geography, as to their options for emergencies.
As I said... an all round bad situation with a horrible ending.