Who is Marianne Alpers from Revolution and what is their importance?

Marianne Alpers, Andi's mother, is a French woman, who makes her living as an artist. After Truman's death, Marianne falls into a deep depression, a depression that leaves her unable to care for herself, let alone care for her teenage daughter. In the end, Andi's father places Marianne in a psychiatric hospital, after which, she is able to to move back to Paris. Andi later joins her mother to attend classes at the Paris Conservatory.