Captains have to sleep, which is why warships have a watch team who are awake. They failed here, which is unfathomable, but that is not, per se, the CO's fault. The CO has to sleep sometime -- I've stood many watches as the senior-most officer awake on a nuclear submarine while my CO slept, and I had to avoid collisions just as much as I would have had to do if my CO had been awake.

It is true that many COs will try to time their periods of sleep for when the operational tempo is lower as a risk management measure. I can only assume the Fitzgerald's CO had made his risk assessment and figured that it was better to sleep at night than to sleep during the day when the contact density would be even higher.

But for a Navy warship being "approached by other ships" is a fact of life for every hour of every day, you can't always plan your sleep schedule for when you're the only boat on the pond.