That only works as long as everything works. Soon as you car breaks down coming back from the gym, soon as your kid has a flu and you've got to take him to the hospital and come back at 2 AM, everything has broken down. Then the next day you can't remain on 9pm to 4am sleep anymore, you're then catching up with the late stuff from day before. Weekends then become compensation for the day before the day before when you had the kid flu and then ....well I've been there, done that, and this kind of schedule simply does not work(for me).
I know many people who I presume like you, let chaos and drama rule their lives.
Shit happens, it doesn't matter if you have a super-structured day or not. Your ability to handle it calmly and with confidence is what makes the difference in how balanced, productive and stress-free your life is.
If you simply regard this as the prototype for a typical day, and not a script that's intended to handle all possible atypical scenarios, then there is no problem for it. As to 4am - 6pm, it's not like he's working solid in that timeframe. He's got personal time (kids, gym, etc) worked in there as well.
All of that is beside the point, however, as this is the schedule that works for HIM. If it doesn't work for you (or if structured schedules in general do not work for you) then you are quite free to simply move along.
So, how is that different than any schedule? If you're working on a 24-hour schedule, obviously interruptions can screw things up. It sounds like he's getting plenty of sleep, so it would probably be okay to sleep an hour less every so often. He probably also has plenty of time on the weekend to reset to his desired schedule if interruptions during the week caused his schedule to shift. I'm wondering what sort of magical schedule would fix the supposed problems you've proposed.
