Try with an alternate surname spelling. There were so many Dutch in British Guyana. It had previously been Dutch. I'm guessing that the name might be spelled DeFries. That would be a Dutch name.
Slavery was way over by 1935. British Guyana ended slavery way before the US did. The family may have moved up to Quebec once slavery ended. They sure would not have moved to the US! They would have been British citizens if they were in Guyana while it was still British.
Give up hoping to get records out of Guyana now. The climate rotted the records, and so many people did not value them. I sent off for some over two years ago and never got anywhere.
I wrote a book for a client tracing her husband's Guyanese family way back. What a kick. But time consuming. I'm better at it now. I had far better luck with establishing online contacts.
Best of luck.