How do i get my parents to divorce?

My father (age-45) has made my mom's (age- 38), mine (age-16) and my sister's (age- 12) lives a living hell. he's currently serving in the indian army and is posted in j&k, so he comes home every 3 months for a month and destroys us mentally (and physically). he abuses my mom verbally and keeps saying that he's earning and paying for everything and that we have to obey everything. he doesn't think of me as kid (never did actually) and expects me to act like an adult (tho he treats me like an animal)) and make zero mistakes. he gets so hyper at us for the smallest things. a latest example that happened last night- mom made tea for herself in a small tea cup, and dad said he wants one too but make it in 'big cup but fill it half only' (this demand has no logic), but by mistake, my mom got him that big cup filled wholly with tea, he lost his temper and started screaming at her tho my mom was nt reply to her, he used such rash language and a very humiliating and high screaming tone that obviously neighbours could hear too, i naturally defended my mom but i did that in the softest tone but that didnt matter to him and he started screaming at my face too. i'm someone who's used to such language and abuse but i break in tears every time this old man screams. both my parents have threatened each other with divorce but none have taken an active step to actually do it. please i want to escape this hell with my mom and sister and want them to get divorced and for us three to move at a safe place. we are currently living at rent but my father has a house on his name (but also his dad's and brother's name.), can my mother file for that flat in alimony? and also my father will retire in 3 years and will get a big chunk of money so will my mom and her daughters (my sister and me ) have a part in it? and also the pension he'll start getting after? I dont know whom to go for help, everyone is aware of my dad's temper but they dont know that my dad has also abused my mom physically many times in the past. i'm thinking of talking about this with my mama (mom's brother) as he's a great mama to me and my sister and i hope he'll support us. but i'm not sure abot his wife and my nani, which is why im hesitating to tell him. i also want to add that this is not an anger problem that my dad has, if it was then he would have fought with everyone and our relatives too, but he never does that, he's super playful and totally another person with them but when it comes to us he's super short tempered. please help and suggest me with something. should i record the fights? and then report it to the police station? will they even help me? im scared that if my dad comes to know about me going to the police he'd harm me and my mom.