Monday Hour One for flex schedules

Hi! I just signed up for certification, and am SO excited to have access to scholars! I have been using MHO for over 6 months and it has been life changing. I recently shared the concept with my husband, but as a construction contractor who owns a business, he constantly fights interruptions in his schedule. On one hand, this means he needs organization even more, on the other hand, he says he never knows when an inspector is going to call and need an appointment ASAP, or a customer is going to call with an emergency such as a flooded kitchen…etc. Do you have any recommendations for applying Monday Hour One for someone who does not know all of the events in their schedule and is constantly needing to rearrange meetings and events? This sounds like so much mental clutter to me; thanks for your help!