I am the godmother to a teenage girl, and her single mother is not expected to survive. I need advice.

So my only sister has stage 4 breast cancer, and the doctors to not expect her to live much longer. She does not have any other relationships like a boyfriend or husband. I am the only godparent and I so very love my niece, but I have no idea how to raise a child from teenage-hood, and guess what? My parents are both dead. I'm kind of panicking. This post might not be made for r/parenting, since I'm not technically a real parent, but I just want some advice. Please help? Thank you very much. via /r/Parenting https://ift.tt/3at1Mmh