He is so hotheaded throughout the book, and then he does a 180 and is contrite. He loved his son, but took his death in stride, then the daughter he ignores dies, and he "takes the veil" so to speak? There is a lot you have to accept in this book, but it seems to me that Manfred, to be true to character, would have to continue to be a tyrant to the end--I can't see him seeking quiet retirement in a convent.