File for divorce on grounds of mental cruelty 

2) seek sole custody of your daughter 

3) take the plea that wife is unfit to take care of daughter on account of her mental illness and refusal to take medication 

Hello, 

1. If she has stopped the treatment through legal means, you can't do anything to resume treatment, unless you hey an order from the court to do so by proving that stoppage of treatment can lead to serious consequences. 
2. In terms of precaution your brother can lodge a complaint at the local police station, a non cognizable one, for the purpose of records stating the circumstances and your apprehensions. In case of any untoward incident, this will come to your aid. 
3. It would be advisable that your brother stays with his wife and child separately to avoid unwanted implication of the rest of the family members. 

With the onset of mental illness, family members experience several emotions and strains. Many relationships have their ups and downs but if one or both people in a relationship is experiencing mental health problems, it can bring additional challenges. Major mental health disorders may be the cause or effect of marital disharmony.
Family members have different perceptions of the problem and have conflicts about the solutions. Family life can become unsettled and unpredictable as the needs of the ill become paramount. Marriage is a contractual agreement which formalizes and stabilizes the social relationship which comprises the family.

When family relationships are stable and supportive, a person suffering from mental health issues or disorders may be more responsive to treatment. Companionship, emotional support and often even economic support can have a positive impact on someone coping with a mental health problem. Negative family relationships can cause stress, impact mental health and even cause physical symptoms.

Sometimes people with mental illness don’t take their medication because they are not aware they are ill. Lack of insight into their mental illness, known as anosognosia, is a common symptom of mental illnesses like schizophrenia or bipolar disorder. So think positively, try to convince your brother's wife for taking medicine with close relatives or a common friend or the doctor who treat her. Advice your brother to train himself to calm down and think before he acts. That way your brother has a chance to evaluate the best course of action for this particular situation.

Don’t worry about a false case from her parents, but your brother should be vigilant or expect such bad things. If your brother wants to save his marriage, then advice him to do good communication with his wife. Good communication skills will help and his spouse works through challenges that arise. Make an effort to develop clear and open communication in his relationship. Good listening skills are critical to good communication. Listening attentively to your brother's spouse will help him to better understand their thoughts, feelings and concerns which will enable you to work together to solve problems. A healthy view of the couple relationship includes having reasonable expectations of the rewards that marriage brings, and recognizing that it still requires personal effort by both parties to make it work.

In a case, where the dissolution of marriage is sought for on the ground of mental illness, then your brother has to prove the mental abnormalities of his wife to such extent, to make him reasonably believe that your brother cannot live with his wife anymore.

Dear Sir/Maam 

As the wife of your brother is suffering from mental illness, it is important that sir keeps collecting evidence such as call recording, audio/video or other wise, specially if the wife of sir makes any threats. In the case sir feels that the wife might take any drastic steps and the family of the wife may file any false dowry or abetment to sucide case, then it is advised to prepare filing for anticipatory bail. if the wife is living with sir collection of evidence is advised. if she is living separately, sir should make a written statement to this at the local police station. If you require any further advice or legal assistance you can book a consultation with me.

Thank you

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1. Through which legal means she has stopped her treatment? Is there any Court Order  restraining anybody to take her for medical treatment?

2. If yes, then an application shall have to be filed before the said court submitting evidence of her ailment seeking police help to admit in asylum for her treatment in her as well as her daughter's interest.

Your assessment is right, if anything goes wrong you and your family will face police harassment for years. It is in your favor to save her and keep her in good health of mind and body. That is the only solution. Apart from all is useless.

Hello,

First of all file a  GD in the local ps againat her family members, and if you want divorce file a divorce suit on the ground of mental illness.

Regards

if you have supporting documents to prove her mental illness which is incurable and that she is not cooperating to undergo treatment, then you an either issue a notice to her parents to take her to their home and get her treated  or you can take her forcibly to their home, drop her there itself, if they still refuse to accept her then you can take her to any nearby mental asylum, get her admitted there.

You cannot keep worrying about it constantly or be under continuous fear in the given circumstances. 

- Your brother or parents should lodge a complaint as information as a precautionary measure before the police after mentioning that she is suffering from mental illness or not caring herself and further some untoward incidents may take place, and if happened , then in that eventuality no family members or husband will responsible for this. 

- Further, you brother can file divorce petition on this ground as well.