Who is Joanne from A Million Little Pieces and what is their importance?

James's therapist and Hank's girlfriend, Joanne is one of the few staff members who fights to keep James at the Clinic even after he gets into a fight and breaks the co-ed relationship rule with Lilly. She guides James through his recovery, including his family therapy. A recovering alcoholic herself, she believes that AA and the twelve steps are the only way to deal with addiction. Quietly insistent, open-minded, and patient, Joanne never loses her temper with James's stubbornness or forces him to ascribe to her belief in AA. She is James's greatest ally among the Clinic staff.