Read other letters about this article
I just read all the comments, then went back to read the original letter. I always find it interesting that as the comments section grows, there are ideas that kind of take hold and become fact when the original letter doesn't really support those ideas. After reading the comments, it seems the daughter is barely able to function...some kind of filthy feral child that can scarcely communicate. (Okay, that may be an exaggeration, but that's the kind of image I was getting.) Back in the original letter, we learn that the girl doesn't take herself for a haircut (not that she doesn't GET haircuts, she just doesn't take it upon herself), she doesn't cook or make her bed. She doesn't dress her self _appropriately_ (yes, she can dress herself for crying out loud). She's dependent on instruction (!), clumsy, sloppy...sounds like a more-or-less typical kid. Maybe a little immature for 16 (still finds boys yucky) but not like off-the-charts mentally ill. Immature is probably not a big surprise given what is described as a sheltered upbringing (I think the word was "opulent", but I'm paraphrasing) and a traumatic family life.
I think everyone freaks out when they read about the "menstrual blood" but honestly, there can be occasional "soiling" of a towel after a shower that isn't like mopping up after a crime scene. Not terribly hygenic--and the LW was right to correct it--but not like smearing herself with feces for heaven's sake.
So, I'm with Allie speaking on the girl's behalf. It sounds like she needs some guidance and has some growing up to do. It also sound like the disdain (I think someone else said "loathing", which seems apt) of the LW aren't going to help her in that department.
I just feel bad for the girl.