The Boy, the Cloud and the Very Tall Tale by Heather Smith
Two years after the death of his mother, Ewan's father was swept away by a magical cloud. Now Ewan lives with his little sister, Flora, his Grumple and his mischievous cat, Kipper. But something about his father's disappearance has never felt right to Ewan. He is certain his father wouldn't leave willingly. When he meets Mr. So-and-So, the owner of the mysterious Notion Shop, he is inspired to take destiny into his own hands. With his grandfather’s most reliable horse, the normally timid Ewan sets off from his home in Bucket Cove on a journey that will test his belief in himself while unraveling the secrets of his father's disappearance. When he is joined by Flora and Mr. So-and-So, he comes to understand that even grown-ups sometimes struggle to process their feelings, and that showing compassion to others is the mechanism through which we can begin to show compassion to ourselves.-Goodreads