The fact he works in an ICU could also mean that he feels any time off he takes could be literally costing people's lives, and that could impact his feeling as if he can't take time off.

The horrendous suffering he has to see on a daily basis could also be why he can't really connect when he gets home, because of compassion fatigue. It sucks, but that's why the healthcare system is in crisis. These heroic people who save others for a living, they are burning out. And that affects everyone.