UpTB,
First, you have to take care of yourself. It sounds as if you are the single most important positive adult role model in the lives of your nieces. The guardianship situation under your mother's roof sounds inherently neglectful of the girls' emotional well-being and beneficial only for maintaining the status quo of the adults.
As minors, dependents, the girls need support for their own perspective, life stage and experiences. Finding social support is essential. Do you know if there is, or could be, a case worker involved or any other type of external social guidance and support for this complex situation?
I am sorry that you are experiencing such a stressful, emotional situation with your family and hope that you will find the support and guidance that you seek. Your instinct to step out of the dysfunction is solid. Stick around. There is
a lot of wisdom here. And for what it is worth, stepping up for those who cannot makes you a strong b-word and not uptight in the least. Hugs to you.
