Many are telling the protagonist to "just tell her brothers about everything that's going on! Tell Eugene about how bad the aunt is and about the sketchy maids!!!"
You really think she can do that? Sure she can, but if I were her, I would realise that Eugene is way too depressed ATM to deal with even more stuff. I would wait until I've compiled a proper case with evidence, while watching the Aunt's movements, and present it with a solution to him perfectly.
He's got too much going on, we can't just go up to him and say "hey your aunt has been abusing me and talking shit about you guys, and I'm not sure but I think she's also been swapping out servants. You probably can't do anything about this though, because she's an adult with control other social circles and the only adult who's taking care of your littlest brother! But uhhh yeah that's going on too."
I don't think I would be able to open my mouth and say that. Although it may be faster to tell him and hope he makes things better, it's not worth burdening him even more.
The world is dark enough for Eugene, better not to bring up bad topics while you're with him, and instead just say simple things such as "have you eaten?" "Don't worry."
It's better for her to keep quiet and observe for now, when the time is ready and she has an actual solution, she can ask for Eugene's help.