Troubled Marriage

File a police complaint and approch the court.

Your brother's wife has nothing to do with your matrimonial personal issues between you and your wife neither you need to respond to her in this regard.

You ignore her or leave the place and stay in some other place to avoid confrontation.

You need to have substantial evidence if you decide to initiate any legal action against her for this, which will inturn will further ruin your own matrimonial relationship.

Think it wisely and take a proper decision before it is late.

You may decide to file a divorce case on grounds of cruelty.

Just file divorse and police complaint too

For giving you concerete advise it is necessary to know that why she abandoned you.

Why did you allow her enter your house after one year of "unknown" separation ?

Her brother can (rather shall) pressurise, harash and humiliate you by filing frivolous case(s) against you and your family, however, it is your decision to sccumb to his tactics or not.

It is better to seek help of elderly respectable persons of family, relatives, friends and acquientaces to find a dignified exit from the marriage by filing a mutual consent divorce.