What’s the relationship between Maggie and Dee?

Dee overshadows and intimidates her little sister Maggie. Dee comes back into her family's life like a tidal wave only to retreat when she is unable to get what she wants. She uses a condescending tone when referring to Maggie like her little sister is a dumb pet. Maggie is afraid of Dee and intimidated by Dee's grandiose personality. It is Mama who finally must stand up to Dee and affords a little respect to Maggie.