Any authority for that proposition? That seems to be contrary to what the divorce lawyers say.
According to the Chicago Tribune, divorce of Obama Sr. and Stanley Ann occurred in 1964. Where and when—presumably Honolulu but I have not yet found that in the record; nor I have seen the actual date in 1964.
We need to identify the court where the divorce occurred; and get a copy of the complaint. In the normal divorce proceeding, counsel pleads the location of the marriage—likely if he did so here, that sheds some light on the facts; maybe if he does not plead where they were married, that suggests a purpose in not doing so.