who do we proceed to get our grandsons adopted?

My husbands daughter has 3 boys (4,2,8mths). She and the two fathers have been in and out of child services for neglect since the oldest was two months. father served one year for leaving baby (2 mths) in ditch, passed out high on illegal drugs. We are currently relative care givers. We are proceeding with adoption. the mother has voluntarily term her rights. All was well to have both fathers rights terminated, until the one on two birth certificates was arrested and is now serving 30 mths in prison. Neither father had done any work on their case plan. He has now done the drug class. the state wants to allow us to adopt the one baby and accept guardianship of the other two boys. Here is the catch - the two year old - he isnt the father. Can we go to court and request paternity? if so, what happens then? dont' want the state upset with us and remove the boys. They are aware that he isnt the father but are going with it cause his name is on the birth cert. We need advise.