Yours is a calm voice here.
I agree...there is much we don't know.
The info I'm basing my conclusions on, besides what I've already said, are that a brother has taken her in and that I've read that lesbian behavior is often a reaction to some type of deficient or abusive fathering. I doubt abusive, but I can see deficient as a real possibility. Another factor is the seeming abruptness of her being out of the house and (this may surprise you, but think about it) her continued defense of he parents.
There are a lot of emotions being expressed on this thread. People are engaged, and that's good. Although I do wish individuals could refrain from namely calling(I've been guilty of that myself).
I'm of the opinion that the grey area is irrelevant. Try to recognize the issue for what it is, and if you can gain insight that will help you understand issues and/or individuals more fully, and improve yourself than this information was not gained in vain. Whether you are a Christian or not. Ultimately, there has been a lot of truth spoken here with regard to our relationship with Christ. That is the most important area one should hope to grow in.
My understanding of that is a lesbian doesn't get what she needs from a same sex parent, a mother. Gay men don't get what they need from a father. I don't know how true any of this is but it does make sense. You go looking for someone who can fill that void.