First, I need to check if this is a published book. I might remember that there are a series of books by R. K. Narayan or another Tamil author that are meant for children, teaching moral lessons through sibling interactions. "Aayirathi Ammayar" and "Akka Thambi" stories come to mind. Wait, "Akka Thambi Kamakathaiyil" might be part of a series by someone else. I should verify that. Maybe the user is referring to a specific writer's work.