How to tackle potential false charges by wives?

Dear Respected Lawyers, I'm writing this on behalf of my brother in law. He recently got married (arranged) to a girl other than his cast. The girl's mom has been very interfering from day one but we still got him married because of the promises the girl made. Now they on their own wish spent on the wedding that was poorly arranged and made furniture for the groom's house (which is his before marriage ). Lately there have been family brawls and some heated arguments between us and the girl plus her parents. The girl and her mom now time and again threaten us with filing complaint with Police and using bad words, they think his sister (my wife) is interfering whereas the girl's mother is the actual reason. We are a bit scared as we have respectable jobs etc. and i feel that the girl may be abusing these laws and playing against our fear of police etc. We want amicable separation we did not ask for any money, we do not believe in torturing anyone and the girl is happily continuing her job and claims she is being tortured. We don't want to be part of the flaw in the dowry law and would like to know how do we get over this? We are ready to reimburse 50% of marriage expense and get a divorce. If gifting Grooms is a dowry then everyone in this country should be booked. Anyone can check our bank accounts if required. We have family issues but not at all domestic violence or dowry etc. Please help.