Please do call someone, this is neglect and is a crime in many parts of the world. Investigate what national help centers/phone lines are available or even better, local ones. Please don't let your own inaction be the reason that you or your sister have something worse happen. The work you may have to do in an environment that actually wants to take care of you and your sister but is foreign to you, is a much better option than the familiar yet indifferent one you are currently in. I wish you the best, and hope everything works out for you.

That is neglect. Please call whatever authorities are relavent in your area (list of DHS numbers for the US: https://www.childwelfare.gov/state-child-abuse-and-neglect-reporting-numbers/) and they can help you.

I hope you and your sister find the support you need.

Once my mom died, things opened up significantly. Just hang in there.

What age? The school counselor may have resources. Your family is not the first to struggle. There are people/agencies who have experience and can help. Do you have other family nearby?

I'm sorry you are dealing with this. Do you have an aunt, uncle, grandparents? Any sensible adults you can call on to help?