Why does Mattie's mother not really live up to their last name Fever 1793?

Mattie's mother does not live up to their last name "Fever 1793" because she is portrayed as a calm and cautious character throughout the book, in contrast to the connotations of fever which suggest heat, excitement, and chaos. Her composed demeanor and practical nature help her remain level-headed in the face of the yellow fever epidemic that sweeps through Philadelphia.