Your mother should report the matter to police. Your sister in law too report the matter of remarriage to police. She should also contact would be wife' s family and inform them about her and your elder brother's first marriage. Without divorce from first wife second marriage is void and illegal. 

Do t get involved 

ask your sister in law to file police complaint of bigamy against her husband and second wife 

Dear,

Your concern for your sister-in-law's legal rights and your mother's safety is valid and deserves careful handling. Here’s a structured plan to address the situation:

1. File a Police Complaint for Threats

• Your elder brother’s threats to your mother constitute a criminal offence under Section 506 of the Indian Penal Code (IPC) (criminal intimidation).
• Lodge a police complaint against him, clearly detailing the threats and requesting protection for your mother.

2. Illegal Remarriage Without Divorce

• Under Section 494 of the IPC, marrying again during the subsistence of a valid marriage is an offence (bigamy). You or your sister-in-law can file a complaint with the police or a magistrate regarding this illegal act.
• If proven, your brother may face imprisonment and/or a fine.

3. Sister-in-Law’s Legal Remedies

• 
  Maintenance: Your sister-in-law can claim maintenance under Section 125 of the CrPC or under personal laws applicable to her.
• 
  Domestic Violence Act: She can file a complaint under the Protection of Women from Domestic Violence Act, 2005, to seek protection, residence, and financial relief.

4. Safety of Your Mother

• While filing the complaint for bigamy or threats, emphasize the need for police protection for your mother.
• Avoid involving your mother directly in legal proceedings unless absolutely necessary, to shield her from stress and retaliation.

5. Counseling and Mediation

• If possible, consider involving elders, family mediators, or counselors to address the underlying issues and de-escalate tensions, ensuring everyone’s safety and rights.

6. Documentation and Evidence

• Collect and preserve evidence of your brother’s threats (messages, calls, witnesses).
• Gather proof of the first marriage (marriage certificate, photos) and the second marriage (wedding photos, invitations) to substantiate the bigamy complaint.

If you require assistance in drafting the complaint or further legal representation, feel free to contact me. Protecting your mother’s safety while ensuring justice for your sister-in-law is achievable with careful legal steps.

Warm regards,
Advocate Aman Verma
Legal Corridor

Only the  wife of person  marring second time have right  to file criminal complaint under Section 82 on BNS. Offence is non-cognizable, file complaint  in the  Court of Magistrate. You can complaint  against threats by brother to mother  to police. They will give her protection.

Your mother herself can lodge a criminal complaint against him for the offences of life threat, intimidation and bigamy on the basis of documentary evidences as well as herself as an eye witness to the second marriage and seek protection besides legal action for the offences committed by him.

1. You cannot do anything. You don't have any locus standii. It's your sister in law who should press the charges. 
2. Offence of bigamy is made out. But the complainant has to be the victim. So as stated in 1, you can't be the complainant. It's your sister in law who is required to lodge a police complaint for bigamy against your brother. 
3. She must also file for divorce before the family court. 
4. I'm willing to handle all her civil and criminal litigations...  But I need an exhaustive consultation session with her first. She needs to visit me for that. 
5. I'm based in Mumbai /navimumbai just as you guys are...  So it shouldn't be much of an issue for her to pay a visit to me for exhaustive consultation. 
6. ९८२०८९७८८४ (nine eight two zero eight nine seven eight eight four) 

Dear Client,

The brother's acts also would come within  Section 82(1) of BNS  for the offense of bigamy in so much as the first marriage had been valid and subsisting at the time when his second marriage was held to have been solemnized.

Your brother's threats to harm and harass your mother amount to offenses under Section 351 of the Bharatiya Nyaya Sanhita (BNS). You can file a complaint with the local police or file a case in the court, bringing to their notice the requirement of protection for your mother. You should include her concerns and the threats she received in your complaint to ensure her safety and avoid her involvement in legal troubles. For your sister-in-law, she may file a case for bigamy and under Section 144 BNSS for relief, or even at the Family Court for the additional relief. It would be advisable to hire an advocate to properly represent your family.

Hope that this helps you to solve your problem.

Hello,

1. You can get an FIR lodged against your brother, on behalf of your sister in law . It is advisable to get her to make the complaint. The offence is cognizable and punishable under section 82 of the BNS (Bharatiya Nyaya Sanhita) with 7 years in prison and fine.
2. As far as the safety of your mother is concerned, she must file a complaint with the police against her son/ your brother for having intimated her and threatened to kill her . It is a very serious offence and the police is ought to register an FIR against him. She can seek protection from the cops. There is no reason why your mother should get into legal trouble for taking steps to protect herself.

1. Your mother has no legal connection with the illegal act of your brother.

2. She can not be charged for attending the illegal marriage of your brother.

3. Your sister in law can file a bigamy case against your brother for which he will be punished with jail term.

You can file any case against him. Only sister in law can file bigamy case against him

- As per section 17 of Bigamy Act, any marriage between two Hindus solemnized after the commencement of this Act is void if at the date of such marriage either party had a husband or wife living; and the provisions of Sections 494 and 495 of the Indian Penal Code shall apply accordingly.

- Hence, the said marriage with the second wife without getting divorce from the first wife is not valid and attract Bigamy as per law. 

- Your sister-in-law can file a complaint before the police against the said marriage , and to stop the same .

1. File a Criminal Complaint for Bigamy:

   • Under Section 494 of the Indian Penal Code (IPC), marrying again during the lifetime of a spouse is punishable with imprisonment up to 7 years.
   • Only the aggrieved spouse (your sister-in-law) can initiate legal proceedings for bigamy. Encourage her to file a complaint at the local police station or a magistrate’s court.

2. Complaint for Criminal Intimidation:

   • Your brother’s threat to harm your mother falls under Section 506 of the IPC (criminal intimidation). File a complaint on your mother’s behalf at the local police station.
   • Request immediate protection for your mother through the police.

3. Support for Sister-in-Law:

   • Your sister-in-law can file for:

     • 
       Protection orders under the Domestic Violence Act, 2005.
     • 
       Maintenance under Section 125 of the CrPC or Hindu Marriage Act.
     • 
       Restitution of Conjugal Rights or Divorce based on your brother’s remarriage.

4. Police Protection for Your Mother:

   • Notify the police about the threats and request protection for your mother while proceedings are underway.

Steps to Protect Your Mother:

1. Written Statement of Non-Involvement:

   • To avoid any legal trouble, your mother can submit a written statement to the police or magistrate explaining that she attended the second marriage under duress.

2. Witness Statements:

   • Gather witness statements to corroborate the threats made by your brother to protect your mother from liability.

3. Restraining Order:

   • Request a restraining order against your brother to ensure your mother’s safety.

Practical Considerations:

• Ensure that your sister-in-law actively participates in filing the bigamy and other related charges.
• Maintain all evidence of threats, including messages or calls, to support your claims in court.

For detailed, personalized advice, consider a phone consultancy. Hope you find the information helpful. You are free to contact me for further discussion. If you could spare two minutes of your time to write a review, it would be greatly appreciated and bring immense happiness to read it. Thank you. Shubham Goyal.