WIBTAH for letting my mother drink so much?

y MIL is basically ending herself drinking so much. I gave her advice and suggested she go to AA and rehab but she responded the most cruel way and just got mad at me for it. My fiancé, niece and I have all given her several interventions, and we even gave her one yesterday. I tried other alternatives after that, considering checking her into the hospital to get her liver checked out (she is jaundiced and is losing so much weight) and to get a wellness check but my fiancé said there’s no point because she will have the option to leave. I tried messaging this rehab facility call center and they said I can try to get a court order or have a policemen do a wellness check but both of those ideas are hard to do without a guarantee she will follow through. So every time she calls I talk to her about other things, and have come to terms with the fact that I can’t force her to go to rehab no matter how hard I’ve tried in the past, so I leave it alone. My BIL eavesdropped our conversation with my MIL and started berating my fiancé for not telling her to “stop drinking” and asking her why her mouth was moving a certain way. He then yelled at us for not doing anything about it, and my fiancé basically had to defend himself and say that he’s tried all that but none of it worked. And so the guilt had settled in. I felt like I am at my wits end trying to help my mother with her alcoholism. So, Reddit, I’m asking you, WIBTAH if I just left this alone?

TDLR; my mother in law is addicted to alcohol and I’ve given up trying to help her. She is getting very sick. WIBTAH if I just let her do what she wants?