My mum is going through a living hell. For over a year now, my single parent sister and her child have lived with her. My mother cannot cope with her but my sister will not leave as she claims she cannot afford to live on her own (she could). My mother keeps having outbursts because she is so frustrated with my sister's behaviour towards her. Almost every day my sister winds my mother up and and then my mother says she cannot stop herself from flying off the handle and screaming at her.