1) If my wife/mother would seek protection order, is my brother's wife eligible to file a case of dowry under 498A. She can file a false case in anger. I have one footage of her violence as proof.
Just like how your wife and mother have rights to file a protection case under DV, she too has a right tfile any case against you people, you cannot stop her from doing so.
2) Can we show that proof/ Video in court when my brother would file a divorce case? What are the chances to get the divorce on that ground.
The evidence of video footage may not be a primary evidence but in the absence of any other proof, it may be corroborated as evidence.
3) How can I lodge a complaint against her as said by Mr. T Kalaiselvan
You can ask the affected person, your mother or wife or both combinedly lodge a complaint with the local police mentioning her torturous activities including hurling abuses in filthy languages and physically assaulting etc seeking legal action for the offences/crimes she commits towards them with the narration mentioning the dates and time of events