What would be the best non-confrontational way of avoiding this abuse I wonder? She has allies she can confide in outside the household, or at least asylum with. It's not like the aunt would harm the other children, it doesn't end in death or stress, in fact it could lessen a few of Erich's burdens.
But that's probably a pitch in a dream, since this girl has already gone through this she's probably not even thinking about alternatives at this point. "I've done this before, I should be able to get it right this time", etc