advice about my parents

so a little back story. my mom and dad are highschool sweathearts. they have me (18) , my sister (10), my brother (9),and my other brother (3). they have been togetger 22 years, married for 19 years. they are Christians, they dont believe in divorce unless spouse cheats, etc. well i live with my in laws as i am married, have a son, and my dad kicked me out for watching a movie that said "god damn" ( he is extreme). him and i we always fight over everything. hes rude and i dont stand for it. especially the way he treats my mom. i want her to divorce him but she wont because shes scared(they have 4 kids and 22 years together). she tells me all the bad things he does. he doesnt hit her but he yells at her, says shes possessed, says the marriage is failing because of her. he puts her down, humilates her. i had to by her shoes because he wouldnt let her by shoes for work. he doesnt let her buy clothes, underwear, bras, shoes, makeup. she cant do her nails, hair, etc. she cant buy anythinf unless he approves n if she does buy it he yells and nags for hours or even days. the other day i was visiting my mom n she forgot to make mashed potatoes for dinner and my dad came home n yelled saying she couldnt even do one simple thing to please him and make him happy (she cooks everyday). she works and shes not allowed to use her money because that goes only to the bills. she is depressed n he treats my siblings bad too. i want to see my mom happy n also my siblings but idk what to do. how to get her to leave him. or if i should just live it alone and let her handle it. i just miss my mom. please help and sorry for tge ling paragraph p.s. also he got all of her credit cards without knowing and cut them in half and tgrew them away