It’s a required scene I think. I went back and did the alternate route where you stop the doll but it still happens. But if you have high enough love with her you can choose to act and it leads to the scenes in season 2 that caps the storyline there.
I haven’t tried explicitly telling her and only her she’s not invited to the party where the scene happens, but I think she’ll just come anyway. All we can do is hope there’s a happy ending in this route cause I’m pretty sure it’s one of the core plot lines of the narrative with how much focus her “condition” has even outside this quest line.
I should also note my original comment wasn’t in reference to successfully saving her it was a vague spoiler free reference to a scene that happens in season 2 that gut punched me. It’s a very beautiful scene and I wish that it stayed that way.