Your sister should file Dv case seek protection order , maintenance, alternative accommodation and compensation 

She can file NC with police against abusive husband 

Her continued silence would only make her husband more bold and desperate for further atrocities.

So she has either the option of leaving her and come back to her parental home or to lodge complaint with local police for the cruelty perpetrated by her husband. 

If she is facing tortures and acts of cruelty she can lodge a criminal complaint against him with the police.

She can even file a divorce case and start living separately away from him.

She has to lodge a complaint against him with all the evidences before mahila police and seek protection.

What to inform, just file FIR. 

- Your sister can file a complaint as information before the police and higher official after giving details of his cruelty towards her 

- She can also approach the Women cell against him on the said ground , however she has following right:

- As per law, A wife has the right to claim decent living standards and basic comforts of life from her husband. Hence for claiming the maintenance for her &child, she should file a petition under section 125 CrPc.

- Her husband is under legal obligation to provide the same to her at any cost, even he is working or not. 

2. Law entitles wives a basic right to reside in the matrimonial/ home, whether the house owned by her husband or his parents, a rented property or officially provided to him. 

- Hence, for claiming her residential right, medical expenses etc, and also for teaching a lesson to the family members of her husband, who subjected her torture &harassment, she should file a petition under the provisions of Domestic Violence Act.

3.  As per the Supreme Court, A wife has complete ownership rights over all her Streedhan, the gifts and money given to her before and after marriage. The denial of Streedhan to the wife makes the husband and in-laws liable for criminal charges. 

- And further, if the husband or his family members subjected a woman to cruelty for the dowry demand, then they can be booked under Section 498-A.

- Your sister should lodge a written complaint against her husband & his family members, in the Women cell/Mahila Police, after mentioning all the details of torture &harassment. 

- The women cell firstly will try to reconcile between them, otherwise, they will lodge an FIR against her husband  who subjected your sister cruelty. 

Dear Client,

It is so bad that your sister is trapped with her abusive husband and she needs to do so much to protect her and her child especially at this times. Its indeed a inhumane behaviour, your sister under section 84 of the Bharatiya Nyaya Sanhita (previously, Section 498A of the Indian Penal Code), can register a complaint against her husband for physical and other forms of abuse and then get a restraining order that bars him from communicating with her as provided by the Protection of Women from Domestic Violence Act of 2005. It is necessary to record all incidences of violence without being violated through the use of pictures and videos in case of threats. She should report abuse to the police since it is her legal requirement in accordance to section 84 of BNS on cruelty. Moreover, she can inform local NGOs or women’s helplines including the National Women’s Helpline 181. She has to visit a lawyer who prosecutes domestic violence cases, and maybe find out how she could deal well with the case.

Hope you find this answer helpful in resolving your problem.