Are You Responsible For Taking Care of Your Sibling’s Children

Sharon is the youngest of four sisters. He older sisters all seem to have some level of dysfunction in their lives. They all grew up during a time of extreme distress in their mother's life. The second oldest sibling was sexually abused by a former stepfather who is now deceased. She seems to be the most emotionally wounded. She has been on drugs, in and out of rehab. Her children, aged 3, 4 and 7, were living with her when she got arrested. Sharon is taking care of them while their mother is in jail. Should she release them to her sister's unstable live-in boyfriend?