Honestly, I'm not too far into the story yet, but from what I've seen, I think the true villain of the story is the brother (intentionally or not)
Like, isn't her obsession with money just a trauma response to her brother's financial abuse? I mean, they can play it for laughs, sure, but that's how I'm seeing it. It seems to come from a place of desperation, not greed.
Honestly, I'm not too far into the story yet, but from what I've seen, I think the true villain of the story is the brother (intentionally or not)