Seeking Advice on Dealing with Family Pain and Infidelity

Assalamu alaikum, I'm reaching out for some guidance, as I've been carrying a heavy burden and don't know where else to turn. My father has been unfaithful to my mother for over two decades, and to my knowledge, this is his third affair. Their marriage has been filled with constant conflict for as long as I can remember, causing deep pain within our family. His spending on these relationships has led to debt that impacts all of us. The arguments between them have sometimes turned physically violent, and I often found myself stepping in to calm them down, almost like a counselor. They would both confide in me, sharing details that were too much for a child to bear. If I resisted or didn't want to listen, I faced beatings. My mother would threaten to cut me off if I didn't comply, while my father simply ignored the situation. I understand my mother is under stress, but her taking it out on me made me shut down emotionally. My father has never been emotionally present; he doesn't even remember my brother's and my ages. He has shown more affection to his current affair partner than he ever has to me in my entire life. My brother, my mother, and I have all witnessed his infidelity. We have clear evidence, including messages and receipts, but he continues to deny everything. The constant lies have pushed me to my limit. I admit that their struggles affected me deeply, leading to a very dark time when I was 15. Alhamdulillah, my mother has since apologized, the physical punishment has stopped, and we've grown closer. I've spoken to my mother about distancing myself from my father after I finish my studies, but she became upset, saying such thoughts could lead to spiritual consequences. The guilt weighs heavily on me. Now living on campus, I dread returning home each summer. She struggles to understand my desire for distance, despite the infidelity and the emotional, physical, and financial harm. She often defends him and even gets upset with me when I stand up for myself, possibly because, as a housewife without family or friends nearby, she feels dependent. I know severing ties with a parent is serious, but the ongoing stress has affected my health, causing conditions like kidney infections and other issues. I've tried everything-prayer, seeking advice from knowledgeable Muslims, practicing patience-but it's taking a toll on my well-being. I never cease making dua for my parents, as it is my duty, but I also worry about my younger brother, who is at an age where he might normalize this behavior. I feel lost and unsure how to make my mother understand that his actions make me want to keep my distance after graduation. Any compassionate advice would be appreciated.