How do Mama and Tilly deal with Cass’s differentness?

Tilly looks out for her sister and acts as her protector, though she cannot understand the depth of Cass' vision, nor, the effect these visions have upon her. In Chapter Three, Tilly also notes how Mama worries about Cass and the potential damage that her strangeness could do to the family's reputation, which is already in question because of their missing Paw.