I'm a former foster youth and I'm not sure if this applies to everyone, but one foster family I was placed with that had older bio kids and one of the problems was their bio kids really didn't understand anything about the foster care system.. They were new and were doing foster-to-adopt. They also had a younger child adopted from another country. I was legally free to be adopted but when they accepted the placement, the foster parents didn't understand I was still in contact with my bio mom and had no interest in adoption (I was 14 at the time). This really confused their bio daughter. I was upset about not being able to see my mom, and their bio daughter felt really put in the middle and also got upset that I was rejecting them by saying I didn't want to be adopted. Older bio kids should go thru some training or at least understand foster care and trauma and also not assume foster=adoption.
Thank you for sharing that you were former foster youth. It's really good to hear from your perspective. I think you bring up a very valid point of having the older biological kids go through some type of training as well or try to gain some knowledge of foster care prior! :)