Thank you for your inquiry. Unfortunately, CHA only works with state registered heritage which doesn't allow to access private information as family records.
As your great grandfather moved to Hawaii in an era where Korea was in a turmoil, it is uncertain that the record you require survived.
We advise you to contact the Ham clan(함씨대종회) where they have the records of the family tree. 함씨대종회 www.함씨.com hahmfam@naver.com