Deborah,

The story of your uncle's passing for white in order to box is very well known. The name changed from Duplessis to Dupas. If you still reside in Louisiana, you should begin with checking census records on the family and birth/marriage records. There are several Duplessis families still living in New Orleans. I was contacted a few years ago by Kelly O'Connor, whose grandfather Edwin Duplessis was a brother to Ralph's dad. Her email is: kdoconnor921@yahoo.com. Best,

Jari