First let me say that I'm not sticking up for Danny boy.
I entered the Marines in 1968 and we had a bed wetter in our boot camp platoon. The way the DI's countered this ploy was to have the fire watch wake the bed wetter every hour to go take a piss. I don't recall what happened to the bed wetter but I do remember the way it was delt with.
Makes sense to me.
Any idea what the reason would be? Does his excuse make sense to you?