If the children have been adopted, it is unlikely that the biological father can regain custody. The father will need to consult with a local family law attorney regarding this matter to see if regaining custody is possible.
The attorney responding is licensed only in the state of North Carolina. This response does NOT constitute legal advice and does NOT create an attorney/ client relationship! Rather, the response is in the form of legal education and is intended to provide general information about the matter in question. Although a response is provided to the specific question, there may be other facts and law relevant to the issue that the questioner has left out and which would make the reply unsuitable. Therefore, the questioner should not base any decision on the answer, but should confer with an attorney in person about the specifics of his or her case.