I totally get this, it's all about routine and familiarity of a situation, we're taught this at school. Our mums would wake us up for school at the same time every morning, we would get up and get ready and leave at the same time, we didnlt have to think about it as we were herded out the door and sent off to school. The assembly bell told us where to be, the lesson bells, the timetable, the lunch bell the hometime bell. We got home, tea was ready, then bedtime when we were told.
As adults we live our life around routine, I know what time to set the alrm for an 8 am shift I know how long it takes to get ready and travel to an 8am shift, I know what time to set the alarm for a 11am shift and how long it takes to get ready and get there, yet if i have to start earlier, or later, i am thrown into the unknown and really cannot plan it out the same way. I have to allow loads of extra time as my routine is thrown.
It's the same with anything I do, if i am going somewhere the next day that is unusual or different i cannot sleep and will panic that If i do sleep i will miss the alarm.
I know that i have to plan an awful lot to get things right, if this man does not have the necessary planning ability, his brain will not be able o cope with the variation of his routine.