Who is Mrs. Frith from A Town Like Alice and what is their importance?

Mrs. Frith has been living in Malaya for fifteen years. When we first meet her, Frith is considered a negative influence on the prisooners. Over time, Frith takes over the care of Johnny, Mrs. Horsefall's son. The orphan serves to change her perspective on life in a positive way, and over time, she becomes Jean's advisor and mentor.