Divorce for 50+ years old female(housewife)

So my father is an electrical engineer and my mom is a housewife. Yesterday my father physically abused my mom again(after like 2-3 years) and I wanted to file FIR against him at that very moment but obviously you know how Indian woman are. She decided to call her useless brother and refused to let me call the police at all so to "protect family image" as she thinks dad going to jail will make it hard for her sons to get any marriage.(we are four sons, all above 18+ and 3 of us are willing to testify in favour of mom the fourth one doesn't like mom but if forced to tell a truth on religious book he will also testify that father physically abused mom alot in past)

Nonetheless I asked her to file for a divorce and live independently of him at the very least and would like to know the options here given these are the main points.

1)My mom have 1 property on her name but father takes all benefits from it(it's just on name) 2) My father have 1 property on his name 3) My father have 2nd property jointly owned by him and his brother 4)My father is an GOVT engineer with salary above 10LPA and is probably gonna retire within 10 years window 5)My mom have never done a job 6)All of us brothers are still in college 7)No FIR exist against him as of now, even the past violence never made it to police. 8)In terms of assets he owns 2 cars and one is in mom's name I think for tax reason or whatever and the rest of the property is mentioned above.

Also one more thing, as you know my mother is "conservative" she isn't filing for divorce right away either. Is there anything my dad can do in 3-4 months of time to reduce whatever support he have to give to mom? I hate this family, their stupid belief but nonetheless need some advice.