Re: MIL- kya karoon inka??? 
Nothing. You don’t do anything at all. And that includes NOT giving your MIL 1 single penny no matter how much she cries, begs, or threatens you. Make sure all your money and jewelry and any other valuables are locked at ALL times.
Let your husband, and BIL’s figure out how they want to sort out the mess their mother made. All you do is support your husband’s decision 100%.