Why is Ultima a welcome addition to the Marez family?

Ultima is a companion to Antonio's mother. Since Ultima assumes some family chores, Deborah and Teresa are happy because it gives them more time to cut out paper dolls and play dress-up. Gabriel talks to her about his future goals of moving his family west to California. Not only does Ultima teach Antonio about herbs and plants that grow along the river but also enriches his senses and soul.