Immediate Need Help - Kindly Guide Me.

I'm 26 years old female , i live in another city for my job . My mother lives with My Father in My hometown. My father is extremely agressive, violent and abusive in nature. My father beats my mom occassionally . They're married for 30 years,i literally don't know how my mother survived. I lived in hostel for almost 14 years. My father had affair, he tried his best to tortured my mom physical and mental both way. My mother had open heart surgery in 2023 and she was a patient of mental illness from almost 2017. My mother's family didn't care about us . I thought if I'll get a good job things might be changed. But from 2022 things get worse , he did every possible things he can do . He abused my mom verbally , beats mom most of the time. Whenever I tried to took my mom with me my father created an emotional drama. We both are exhausted. I'm also suffering from severe anxiety . My father threatened us . If my mom said about police complaint he threatened that he'll show his psychiatric prescriptions and after discharge from police custody he'll kill both of us. Even my father called me over little things whenever I was in my workplace. He knows I stay away from them , i already suffered from anxiety attack. I'm a single child . My mother condition is extremely bad , she's mentally unstable. But my father's behaviour became intolerant day by day. Please guide me What should I do. My mom is extremely afraid from police complaint, even she loves my father too much. I don't know, I'm shocked and speechless both at the same time.