My (23F) mom (50F) is turning toxic, or maybe she always was and I didn’t know it.

My (23F) mom (50F) has been turning more and more toxic over the last few years. When I was growing up, she always was supportive of me and my three sisters (17F and 25F) and I loved spending time with her. As I turned into a teenager, I noticed she would occasionally say a rude remark about my dad (51M). It was usually about how she doesn’t enjoy doing romantic things with him or that she didn’t trust him. I also noticed she listened less when I would talk about my day, instead interrupting me to talk about her own day. She started drinking a lot more the past few years, or maybe I just started noticing it. She makes a lot more comments about her weight and how she hates her body (she is around 20lbs lighter than me with a similar body shape, so it’s hurtful). People would probably refer to her as an almond mom, something that is toxic for daughters to grow up around. Since COVID, she’s been significantly more hurtful. My dad lost his job, and she constantly made remarks as if it was his fault his industry tanked, resulting in mass layoffs. He tried going into business for his own, but made significantly less money so my mom wasn’t supportive. He since had to move to another country to work, and is only in town for one weekend a month. When he is in town, she often brushes off spending time with him. Whenever I come home now (I on-line with my partner) she only talks about how much she is irritated with my dad and threatens divorce at every turn for the smallest reasons. This includes things like he didn’t want to give me an absurd amount of money for my wedding (I never asked for a dime) or because he didn’t want to spend a minor fortune to buy a beach house for them to retire in. My family went on vacation without me because I was working, and my little sister (17F) texted me saying my mom was angry drunk. She reportedly spend hours accusing my dad of wanting to be around the prettier/younger girls, and yelling at my sisters for going to the Spa and not letting her into their hotel room. My little sister apologized to my dad for how my mom was treating him, but he just said he’s used to it. Is there anything I can do to try to help this situation? I feel helpless and my loved ones are more distanced than ever.