I dont understand, why the boy is split from the group?
The DM/ instructor made a swim for an island. Ok.
So there are 3 divers left. Why did they loose the boy? Was the dad one of the missing divers? So if he says his son is death, he saw how he died? And let him drift? That is understandable. But why did it take 2 days to tell him his boy is not alive?
Seems odd, maybe i missed something?
We don't know enough information to assertain what happened from the time they surfaced and found the boat missing/out of sight/not in the location it was supposed to be at to the time they were rescued to make any concrete assumptions yet.