You're right - that would not help. Stick with your plan to be sure he attends, even if it tugs at you. This type of regression is not uncommon in the wake of the types of family changes you describe. Outside of school, try to have him involved in some form of structured peer group experience, even if only for one time each week. He'll likely be fine. The best predictor of the future is history, and his history is that he made a good adaptation to preschool.