What is Nancy's relationship with Penelope?

Nancy spends her time fussing over Penelope, although she brings nothing constructive to the table. She demands that Penelope find constant help and avoid going into the garden, where she feels that Penelope will strain herself again. However, she has neither the money nor the inclination to help her mother herself. She thinks about the past and her "darling" Daddy and the only woman who really understood her, her grandmother Dolly Keeling.