I'd take it as a good thing, since they're not traumatized in any way or amount with him gone.
I remember when I was a kid and my dad had to go for a month for some job-thing. My mother was seriously traumatized not to have him home at night. She rigged burglar alarms for all the doors and the milk chute (the milk chute!?! Our dolls couldn't even stand up or lay down in there!) with cords leading all over the place. We'd have to detangle everything to get breakfast and go to school. It was really silly. She told him emphatically that he was never doing that again when he got home--and he never did. Anytime he had to go, she went with him. Ever have a babysitter for a solid week? Not fun.
Anyway, I'd take it as a good thing--unless they're not happy to see him when he gets back.