Helping My Sister Who Has Depression

My younger sister has been diagnosed with depression since she was in middle school. I think she was wrongly diagnosed. Ever since then, she’s taken on the identity of being depressed and it just being part of her. She’s going to therapy and is on medication to this day. It breaks my heart to see how she’s identified so deeply with depression because I know that’s not her. I know she’s more than that. I see her spiral out of control in negative emotion about simple things like changing jobs and moving houses. I know learning the model and doing this thought work would tremendously help her. She already is deep into meditation and the model takes it even further. I feel hopeless when I think about her. What can I do to help her?