So while I agree to a point with Chaos I suspect there was a bit more than what was in the book. I don't think it's normal at all for a kids to be playing Hells Angels Sex slaves at 8, that seems off, couple that with the graphic talk of jerking it in the bed with your sweaty little sister things become even more suspect.
The sister is now gay, most gay people are either born or they are made. When they are "made" it tends to be because something happens to them while they are growing up that shapes their sexual tendencies.... It could be abuse it could be other... I dunno and I do not belive that being gay is bad. Vaginas, assholes, mouths whatever so long as it's consenting. That being said her constantly fucking with her sister by making her a hells angel sex slave, kissing her and jerking in bed had an impact that's undeniable and these are just the things she wrote about.
What bothers me more than anything with this Lena chick is her overwhelming lack of self awareness and her bullshit qausi-feminist ideals. Her shit stinks and she needs to smell it. Imagine if this story had been penned by the GoP guy who "raped" her.