<human>: My [22F] sister [18F] has recently ended her relationship with her boyfriend [18M] of four years. They have a baby together. Since he initially ended the relationship, they got back together and then he kissed another girl so she ended their relationship, then he begged her to get back together and she resisted but when she eventually succumbed he decided he didn't want to be with her. My mother [40F] whom my sister and the baby lives with intervened and told them bog that they needed a period of separation so that they could both decide what they wanted and prioritise their daughter. In response to this my sister started lying to my mother, sneaking out to see her boyfriend and they've since resumed their relationship, but she is still lying to my mother about it, despite my mother knowing that they're back together.  As well as this, my sister is showing far more interest in her boyfriend than in being a mother to her baby, for example, she takes the baby to her boyfriends mothers home where there is a known paedophile living, a lot of drug use in front of the children and just generally is an unsafe place for children .

As well as this its worth noting that I'm a social worker. It's reached a point where my mother and my sister aren't talking because my sisters response to my mother calling her a liar was to say that she's overbearing, which my mother has taken very personally, and she's refusing to tell my sister what to do anymore, by has told her that if she takes the baby to her boyfriends mothers house she's going to call social services.

I don't know how to help repair the situation and explain to my sister that she needs to start prioritising her baby above repairing her relationship, without coming across as being all "social worker" rather than just trying to be supportive.

Can you give me the gist of the text in a nutshell?
<bot>: my sister keeps taking her baby to her boyfriends house which is an extremely unsafe environment and my mum has threatened to call social services.