On the fourth day...

Ridge finally asked where his brother was.

Archer rode his bike to school so there was no "goodbye" as he hopped out of the car. When we returned home from dropping Em at school,

Ridge: "Archer? Archer?"

Mom: "Archer's at school."
Ridge: "Oh, school. Emma school?"

Mom: "Yep. Archer and Emma are at school."

It only took four days. I think Ridge is enjoying his time without any sibling intervention. He is starting to roam free and redistribute the contents of his siblings' rooms. Maybe, just maybe this will encourage Archer to clean his room and put things away that he doesn't want re-routed! A mom can dream, can't she.