I recently saw something regarding this while looking through Hawaiian adoption law during a discussion. I seem to recall reading that the Father absolutely has the right to allow or deny an attempt to adopt his child by someone else. I wish I had saved it at the time, but I think I can find it again.
For me it was a sort of Eureka moment which helped to explain why Barack Sr. came back to Hawaii in 1971 on "family business." I don't have time to look it up right now, but I will try to do so in the next few days.
If you find it, please let me know. I’d be interested in reading it.