My 13 year old niece lives with my sister, her abusive alcoholic husband, and her three other children. I am seeking legal advice on how in the state of New York I can get her out of this home.

She is the only one of the four children who is not the child of my sister's husband. She expresses repeatedly her extreme situation and her intense desire to be taken out of the home. She expresses her upset and disdain for the way she is treated by my sister's husband and her witnessing him saying he is going to "beat and kill" my sister, among other daily abusive language to her and the children. He tries to step in to discipline my 13year old niece and yells at her with demeaning and abusive language. He has denied her food in the past. He accuses her of behavior she is not engaging in when he is drunk.

We have done an intervention with my sister about 12 months ago and it was ineffective. All the children are in extreme danger with both my sister and her husband but we are trying to focus on getting my oldest niece out first. She has begged my husband and I to get her out of the home. Her biological father is not in the picture other than an occasional visitation and does not reside in a permanent home.

I am in need of legal advice in the State of New York on what the best way to go about getting guardianship of my niece is. In addition, I am seeking advice on the best way to get my other 2 nieces and nephew out of the home as well. They are all subjected to daily verbal, emotional, and mental abuse - all of which I have witnessed - and are living in unhealthy conditions.

Thank you.

The only way legally that I know of that you can do that is call child protective services
And tell them everything. You can also tell them that you are a relative and would be willing to take her in if possible. You do run a risk of them going into the system though rather than turned over to you, but that still sounds better than them living with a ticking time bomb.

You get your sister and all of her kids to move in with you temp or to just move out. Your sister is allowing this behavior by first allowing him to do this and also by not leaving.
Next you can report this to children and family services, and of course all of the kids and the sister will need to be honest when they investigate

Yeah if the mother is willing to leave him that is a good intervention
Often, unfortunately, the mother will pick the guy over the kids and/or think they can go on having both no matter what anybody warns and they will not wake up to reality until it is too late.