Duke was the widower of the former Betty Summerlin, who died at the age of fifty-six on February 26, 1982.<ref>{{cite web|url=https://old.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=Duke&GSbyrel=all&GSdyrel=all&GSst=20&GScnty=1148&GScntry=4&GSob=n&GRid=98915753&df=all&|title=Betty Summerlin Duke|publisher=Old.findagrave.com|accessdate=July 23, 2018}}</ref> Duke died four years after his wife and three days before his 61st birthday of a lengthy illness in Rapides General Hospital in downtown Alexandria. He is interred at the Greenwood Memorial Park in neighboring [[Pineville, Louisiana|Pineville]]. His surviving son is businessman L. Brian Duke, Jr. (born September 18, 1948), of Alexandria. | Duke was the widower of the former Betty Summerlin, who died at the age of fifty-six on February 26, 1982.<ref>{{cite web|url=https://old.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=Duke&GSbyrel=all&GSdyrel=all&GSst=20&GScnty=1148&GScntry=4&GSob=n&GRid=98915753&df=all&|title=Betty Summerlin Duke|publisher=Old.findagrave.com|accessdate=July 23, 2018}}</ref> Duke died four years after his wife and three days before his 61st birthday of a lengthy illness in Rapides General Hospital in downtown Alexandria. He is interred at the Greenwood Memorial Park in neighboring [[Pineville, Louisiana|Pineville]]. His surviving son is businessman L. Brian Duke, Jr. (born September 18, 1948), of Alexandria. |