A sister of mine acts toxic around people who are close to her, or live with her. She attends therapy regularly and brags about how wonderful her therapist thinks she is in dealing with her trauma. It seems like she goes to therapy to get praises from her therapist and feel good about herself. Her toxic behavior has not changed over the years because she will not show her true color at therapy. She goes there as a victim recovering from someone else's abuse.

How can I get her to be her true-self and honest with her therapist? She is a completely different person behind closed doors than she is in public or with her therapist.