Whilst fatigue may well have played a part, it is interesting to see that the accident flight and the previous two night flights are flights the f/o had bid to operate (indicated by the "R" at the bottom of the column for Friday - the day they reported for work).
I would not contest that this may be a fatiguing work pattern, but at the risk of being flamed would suggest that you can't really ask to fly three nights in a row and then complain about being fatigued. Whilst it may not be fashionable to defend Flydubai in this thread, I am far junior to both of these guys, but on the same day operated a much easier flight ending about 9pm local time, so presumably had they bid for day flights they would have got them, as I did.