my nan is a pos

She refuses to help me with my siblings. she actively undermines me all the time and makes my life even harder. Im begging her to try to get guardianship of them because my mum is off drinking herself to death and they need a guardian who isnt 8 hours away and been gone for 2 months. Nan just says no, she doesnt want to look after them. Which is FINE because i have told her i will look after them. I just need her name on the papers