the question is why is she protectin the female leads brother tho, can someone fill me in?

So she wont die

My limited understanding so far, is that the novel our FL is trapped in is quite twisted - in the way that the original novel's MC has to go through a ton of disturbing stuff that her love interests put her through.

And our FL, a side character of that novel, is supposed to get caught up in that mess somehow - which hasn't been revealed yet(?).

However, the original MC's fate will begin to unfold according to the novel only when her brother Cassis is killed by the Agritche Family.

So, in a reverse domino effect, if FL ensures Cassis is alive and well, then the novel's MC will not realise her fate, and in turn Roxanne(the FL) will get to live longer.

so thats y she helped him, deym this story super sophisticated. Thank youu tho : )