How do you deal with a problematic family but also you are too attached?

I (29F) am a doctor and recently moved back in with my family after 10 years away for studies. My brother also lives away, so for the most part, it’s just me with my parents now. From the outside, we look like a well-settled, happy, educated family—my father had a stable job before retiring, and my brother is also well-settled. But growing up, I saw a different side of things. My father was always a great dad, but he was never an ideal husband. He constantly did the opposite of what my mom wanted, and over time, their relationship soured. My mom gave everything for this family, and she has no real support system—she lost her parents early, her brothers, and even her cousin recently. She also has several chronic health conditions, which makes things even harder for her. For the past 10–15 years, she has been cursing my father out of frustration. At first, he ignored it, but now their marriage has become worse. I can't even explain the level of toxicity, but the fights are constant. Even though I feel that deep down, my mom doesn’t truly mean the things she says, my father has started taking everything seriously now. It’s just a bad marriage, and they won’t separate despite how miserable they make each other. I feel torn because, on one hand, I know their relationship is toxic, and being around it affects my mental peace. But on the other hand, I’m too attached to them, especially my mom, given everything she has been through. My brother and I have suggested that they live apart, but they refuse. I don’t know how to navigate this situation without feeling like I’m drowning in their issues.