dear ben
i had the same situation kind of. i can only tell you that your mum has to find her way out without you. she is co-depending from him. my mum was too. then we got a big fight and she chose his side. we had no contact for 3 years, but it seems it helped her to find her own way. i was not there available for her to talk about her problems, i allowed her to unload her problems on me and in the end suffered from anxiety and panic attacks.
i am not saying that you should stop seeing your mum or else. i just wanted to show you that whatever you do, it is not your burden. she chose this man. of course you are also suffering from the situation. i find it really good that you acknowledge that you have a life on your own. that’s very important. you cannot spend your life and energy on other people, even if they are your relatives. if it makes you sick, it’s not okay. i’ve been there and i got very sick for years.
since i started to care for myself lots of things have changed. my mum got the chance to finally realize that i am not always available for her. it forced her to stand up and start to act instead of only argue about her situation.
i also see today, that caring for myself helped my mum to start caring for herself too. be a good example. live your life, also tell if you don’t want to hear about it again. make sure to keep a distance and to protect yourself without being unfriendly.
believe in your feelings, follow the ones that feel good to you and good things will happen. you are so young. enjoy your life. it’s precious and so are you.
you ask in your last sentence: “What can i do”. think about that doing “nothing” is also an action. don’t feel bad about it. your mum is an adult. she’s old enough to take care of herself. it’s her task. i know that we children like to help our parents and especially with dysfunctional families with alcoholic problems. we feel helpless yet we try eveything to make a change. but it is not up to us. we can’t to a thing. just encourange. you already do it. i feel you do everything right. i really do.
all the best