Guideline on Divorce from Husband on Ground of Mental and Physical Cruelty

My sister needs Divorce from her Husband on the Ground of Mental and Physical Cruelty. My sister got married two years ago and she has no children, and now she has been living with father for the last 6 months. She is continually facing problems from her husband, and she decided that it is impossible to stay with husband and need divorce. Our family requested her husband for mutual divorce even without any Settlement Amount, but they are not ready for that. Kindly guide now how she can get divorce as early as possible. I know that it is not possible very fast. Whatever kindly suggest the best path in the view of CONTESTED DIVORCE step by step (In details of rules and act etc), So after a certain time she will definitely get a divorce. Her husband is financially fulfilled, also guid that, Can she file petition for maintenance Or Interim Maintenance or Settlement Amount any kind of etc. Also guide can she file a complaint (For her Justice) on husband on the Ground of Mental and physical Cruelty, if yes then guide step by step in details. In that way, maybe the husband gets ready for mutual divorce. Please guide on details.