Stress or boredom that he himself might not be able to articulate, maybe? Was it the other twin who recently had surgery? Does he perhaps perceive that William got more attention during this time? Sometimes a kid might resent a sibling with a health problem, but then they feel guilty about these feelings and act out. You are on the right track with therapy and keeping their schedules regular, and Mary's dietary suggestions are helpful. Mostly show them that although you and their father are divorcing, you won't EVER divorce them. Hang in there. Sharon