Mitchie Mouse Mitchie Mouse is a little mouse with a big heart who has experienced something no one should have to go through—he lost his brother. In the book “The Day Everything Changed,” Mitchie takes us on his journey through the land of grief and shows us that you are not alone with your feelings. Written by clinical psychologist Carine Kappeyne van de Coppello, who has over 30 years of experience with grief and children, this story comes from a warm heart and extensive experience with children who have suffered a loss.