Adoption

I have two sisters here and another girl, sisters are up for adoption but their father is very much in their life, but has no parental right,
It is amazing the amount of inquiries their case worker has received about them from all over the USA. but is also concerned about what they really want. The other option is long term foster care, which could keep them here till they are eighteen.
The question is are they really adoptable, one of them is sure it is her way out of the foster care system, the younger one I am not sure about yet.
I would hate to see them adopted and seperated but that is looking like the way it will go.
Do they really understand what it will mean to them to be adopted, maybe I will make it a point to talk more with them about the adoption process, to hopefully let them really grasp what it will could mean for their lives.