If DHS has custody of children, can one parent give rights to a relative permanently?

We need to know more before we could answer this question. If father has custody of the children under a valid court order or a judgment of dissolution or affiliation, and the DHS has removed the children from his home for reasons related to the way they have been treated, then any attempt to allow his aunt to adopt them would require him to file a motion for modification of the original judgment and that motion would have to be served on the mother of the children. The standard the court would apply is "best interests of the children" and the history of both parents' relationships with the children would be under examination by the Court. The only was the Court could give custody to someone other than one of the parents would be if it found that both parents would present a threat of inappropriate conduct with the children. If the Court did find that it was in the children's interest to be placed with the aunt, that would probably be a temporary guardianship with the possibility of review after one or both of the parents' circumstances had changed.