Adopted daughter's sibling rights

My daughter was adopted from foster care nearly 10 years ago. Several years ago her mother had another child. Mom is still in and out of prison. My daughter's sister is with the new baby daddy, also a drug dealer in and out of jail. Why the child was not removed from the home I have no idea, except maybe there isn't enough foster homes. So they really don't tell you about this one when you are doing foster care and adopting. They don't tell you that you will have another child that you will never see, know that she is in unfit conditions and that you will be powerless to do anything about it. As my daughter's mother, I'm responsible to protect her rights until she is old enough to protect her own. You often hear about grandparent rights but you seldom here about sibling rights. In my opinion my daughter's sibling rights were not terminated when her mother's parental rights were removed. I'm not some lunatic mother who wants to steal this woman's second child but when I'm out shopping and see the "sisters" girl shirts for frozen, I think of my daughter's little sister. For a minute I think, I should buy that for . . . It is disturbing. When I know things aren't going well with her family, per face book or I just get a nagging feeling, I get the urge to buy a booster seat, get in the car and just plain go get her. Don't get me wrong, I know that is not possible. So my point is, I just want to say somewhere out there is my child's sister and there are times when I feel like I have a missing child. I don't really know how my daughter feels about it because she still hides her feelings. I suspect she worries about her. My points are it is a pain always in the back of our minds. The other point is, if something happens to her parents or the parent rights are eventually terminated, I think my daughter should be able to have some input into her sister's future. Neither one of these children did anything wrong and their rights were not terminated.