Claiming Maintenance

1) I am a 29 year old. 2) Since 2012, my father(Central Govt. retiree) started living separately from my mother(unemployed, unskilled housewife) and me. 3) He lives in the first floor of the house which is his own and constructed by him. My mother and me are living in the ground floor of the same house. 4) He does not pay any maintenance to my mother(I am looking after her). For shortage of space in his first floor abode, he deliberately has left behind few household articles originally bought by him like sofa, fans, beds,stove & appliances like fridge, washing machine etc in the ground floor itself which he keeps using frequently and goes back to the first floor. 5) Although abandoned without maintenance, since my mother is i) "taking shelter" in my father's house ii) using some of "his" aforementioned things iii) and also being financially looked after by me - does this deny her the claim to maintenance from husband? 6) If maintenance is granted then can it be claimed retrospectively(i.e since 2012 January)? 7) When my mother had asked him why he abandoned her and demanded in frustration that he pay her some maintenance, he dared to do her worst! Several years ago he and his siblings and mother had insulted her a lot which she bore for myself. Even today they all occasionally sojourn in my father's 1st floor house and have a gala time, even while passing snide comments on my mother among themselves when they happen to pass through the ground floor proceeding towards the main gate of the house! Having had enough of this anguish, she now wishes to have a legal remedy to her plight. Can she file a Domestic Violence against all of them incl my father?