Maintenance application by Step Mother when Father is not allowed to stay with Step Mother

My Father married my Step mother after my mother died, I am the only son and my sister was married prior to their marriage, I got married 3 years back and since then my step mother was forcing my Dad to change all the property in her name, I am staying with my wife ,kid in Chennai and my father was staying in Kerala with my step mother, My dad already has fixed deposits and 6 lakhs in my step mothers name at this time. She left the house for 3 days without informing and was not accessible after a argument with Dad and my relatives, We filed a missing complaint and my dad is 72 years old and hence he decided to stay with us, My Step Mother continued to stay in her relatives house and filed a domestic violence case against my dad and myself , The Sessions court provided her rights to stay in the house (which is jointly in my fathers and step mothers name) and passed order that my dad should not disturb her, She refused to take care of my dad and is staying in the house, She has filed Interim Maintenance application of 20k and my lawyer is requesting my Salary Slip and ITR details. I would like to know 1) Is its applicable that i (StepSon) should share my details of income along with my fathers income details for the maintainence application filed by my Step Mother. 2) My Father would like to live with my Step Mother in his house, but Court has passed order not to disturb her, 3)How do I discharge of this maintenance application.