In fact if he was doing his job properly he would have been monitoring the F/Os performance throughout the flight. It was not suggested in the report that the F/O felt pressured to fly home but that he took two controlled rest breaks.
Australian F/Os are so so good that they don't need monitoring, PIC was so cocksure that he had a top notch ace in the right hand seat.
Makes a mockery of telling the pax to turn off their mobile phones due to possible interference with the avionics. Do as I say not as I do!!!
Hey, ATC communication in Asia can get quite bad, so the Captain might have been trying to communicate with SIN tower through the mobile, maybe using text messaging?
There are so many mitigating factors on top of the one regarding fatigue.