What plans did Mrs. Bowles have for Susannah?

Mrs. Bowles wasn't taken Susannah in as an orphan, she was taking her in to help care for the younger children.

“You are much more than a girl, let me assure you of that. You are older than Susannah there.” She inclined her head toward the girl with the dirty neck. “She has lost her family, but we are not taking her in as an orphan. She will help us with the younger children.”