Euro control online training centre has an interesting mini course on Fatigue Risk Management.
Fatigue Risk Management [SAF-FAT] (Restricted) is title.
Have a look.
We had a guy who commuted and occasionally spent his lunch times sleeping in the TV room which was awkward for everyone else. From time to time a search party had to be sent.
make sure you wake them so they have 10 mins to get there heads together before having to do anything sensible
Defiantly agree here.