Should I tell the school counselor?

My friend Zoey has told me a lot about her family in the past few days. Her mother is an abusive alcoholic who has even proved her crudeness to my family (we're neighbors) when she came upon her porch while drunk and rudely yelled some hardly legible and irrelevant insults at me and my sisters while we were outside playing in our yard. To say the least, the woman's full out bonkers, and Zoey's stepdad, who she said she didn't trust either, recently divorced the woman, taking Zoey's two half siblings with him to New York. She told me she's scared of living with her mother by herself, seeing that her mother drinks, doesn't have a job, and often brings home random men from the trailer park next door.

I told Zoey that she should talk to the counselor, but she doesn't want to leave her mother seeking as though her mother is already in a mentally distressed state from the recent divorce and what-not, and she was scared of living in a foster home where she won't know who's taking care of her.

Still, I feel as though I should to something to help her. Just the other day, Zoey's mother ordered her out of the house for talking to her stepdad (before he left) and told her to leave. Zoey walked down the road for quite a long ways before her mother's friend picked her up and took her to her house.

I know from stories that foster homes can be just as bad as home. Should I betray my friend and tell the counselor, in hope that it may get her some help? Or should I leave her and her mother to themselves?

Say if I did tell the counselor, what would they do?

your answers are appreciated. Thank you :)