State statutes generally have a very strong presumption for placing children with biological relatives. This certainly preempts foster care parents. Only in a case where the county terminates parental rights is foster care adoption allowed and all possible remedies must be exhausted before that can occur.
In short, your case is not unusual. The county would, in al,most every case in every state, have to explore every reasonable way to reunite the child with its biological relatives before an adooption could take place. If there is no evidence that the grandparents endanger the child, the outcome that you relate would have been predictable
