DD has always been an intense and strong-willed child so I've gotten used to non-compliancy at home although she is slowly maturing and she is less defiant or rather, she has gotten more charming about being defiant so things have improved at home. Her behaviors in her ballet class, however, has definitely regressed as she has mentally checked out.
Do you know how your DS is feeling about his school? Has he clicked with his teacher and classmates? From what I understand, most Montessori schools do not like parents in the classroom but maybe it'd be worthwhile to observe discreetly one morning to see how he is doing.
This phase might last longer than you'd want it to but it too shall pass. At least, it's a good practice run for adolescence. I for one am hoping that DD wouldn't need to rebel during her teen years because she has gotten it out of her system during the last 3 years.
