He forged one because he doesn't have one.
I have no doubt that he has a Hawaiian birth certificate from 1961. I have doubts that what he presented is said document, and I suspect he has gone to great lengths to make sure no one can see what is on his actual and Original Hawaiian birth certificate document.
I suspect it indicates that he was not born in a facility where the facts can be verified. I suspect very strongly it lists his as an "at home birth." I suspect his mother was actually living with Relatives in North West Washington State, or Canada when he was born, and he ended up being born in Canada, with his Grandmother alleging he was born at home in Hawaii on his paperwork.