advice on divorceeeeeeeeeeeeee

My father is an alcoholic, has allegedly cheated multiple times, has been physically abusive toward my mother, and contributes very little to the family despite being a government employee. My mother, brother, grandmother, and I are considering divorce as a possibility in the future, though no decision has been made yet.

The old house is in my grandmother’s name, and the newer house is in my mother’s name. My father did not contribute financially to either property, but still claims ownership.

I have three questions:

1. If my parents get a mutual divorce, can my mother continue living with me, my brother, and my grandmother, or would she have to return to her parental home? Can my father be made to move out?

2.If my mother files for divorce herself (contested divorce), would the answer regarding residence and my father’s right to stay in the house be any different?

3.What are the approximate costs of a mutual consent divorce versus a contested divorce in India?

I’m only seeking information at this stage; no decision to file for divorce has been made yet.