1. Who is the owner of the house? If the owner is either of your parents then he/she may file a suit for eviction of your brother's wife from the house. She has no right to reside in the property of her in-laws without their consent.

2. Furthermore, you say that your mother is also being 'tortured'. She may file a case under Section 12 of DV Act to seek immediate relief of protection order from the court to bring an immediate end to acts of domestic which she is suffering.

1. Yours problem at parental home is more like a personal one than a legal one.

2. Try to stay separately in the same house so the interference of your SIL remains minimum.

3. Your SIL is not a person who is serious to lead a happy married life and is hence is taking this opportunity to create chaos at home.

4. Ask your brother to stay in separate household for sometime till peace come back.

5. Try to revive your marital life amicably. 

Stay separate in rented flat 

2) seek maintenance from your husband under section 125 cr pc

3) in alternative file DV case against your husband seek protection order, maintenance and compensation for mental torture undergone by you 

4) your mother can file DV case against her daughter in law , son seek protection order, maintenance and compensation for mental torture undergone by her 

See firstly you and your mother can file a complaint of mental cruelty and for intimidation agaisnt the sister in law with mahila police.

Further in case any FIR or complaint is filed you need to seek anticipatory bail and apply for quashing before the high court.

You can stay separately along with your mother away from your brother and his wife. As you are independent tgerw is no need to stay with him. If the house is ancestral then you can file a partition suit against all the legal heirs.

Regards 

If your mother is senior citizen she can file case under senior citizens Act against her for all the harassment and evict her from that house. You can also file domestic violence complaint against her for such harassment

If the house belongs to your parents, they can application in court to evict her. Ask brother and wife to live separate. You have same right as of son to live in paretns house. If your parents are soft and concerned for you, oust them out.

you can stay separate.

Your mother can also take legal action against your brother's wife.. 

if house belongs to your Parents then your parents can ask your brother and  his wife to leave house and stay separately. 

Hi

Since already you are in a disturbed state of mind and position, and that, you are also working.

One of the possible options could be, go for paying guest option / for Hostel / work out any other possible options you have considering your position, and that, you can also take your mother alongwith you if circumstances permit. 

Instead of precipitation the matter / disturbing the lives of your brother (and his family), your mother and last but not least your personal life.

Sum and substance is that, work out modalities and opt for best possible option apart from above mentioned.

Good Luck

Since you are already facing troubled marital life, it would be better that you dont get into more such troubles from your sister in law.

If you want to be safe and free from her troubles, you may better make an arrangement to stay outside your brother's house along with your mother so that she is also safe and secured.

This separation may bring you some relief because you will be supported by your mother and she also may have a support from your side and you both can live peacefully.

Legally you cannot take any action against your sister in law because you are not living in your matrimonial home and this house is her matrimonial home, she can level any allegations against you which may hamper your day to day routine life also.

1. As per the information mentioned in the present query, makes it clear that you have been dragged into unwanted quarrel and litigation without even having any involvement in it.
2. This is also true that whether you are innocent or not, will be proven at the end of the trial and till then you will be harassed for no reason.
3. In the mean while, I would suggest you to keep alert and have some proofs recorded in your favour.
4. As you are stating alone, if you wish then you can file an application for quashing of your involvement in the case before the court of law.