Hi Tim, Ancestry.com has a database of Minnesota births that you can access if you have a membership or via your local library. Otherwise other volunteers can search for you and send you the information via private email on these living people. The search may turn up the correct name for Gene, as it does include births of modern-day people.
For the record your dad was born 16 February 1934 in Faribault County, Minnesota; his mother's maiden name was Nimz. His parents may be John Hinz b 1891 and Hulda Nimz, married 17 March 1925 in Martin County, Minnesota (Minnesota Official Marriage System). Siblings may be Vera Lulla, Kenneth Orvall, and Keith Wayne (Minnesota Historical Society birth index).
Les died 22 November 2006 in Red Wing, Goodhue County, Minnesota.
Minneapolis Star Tribune obituary, LINK:http://www.legacy.com/obituaries/startribune/obituary.aspx?n...
Resided at the Red Wing Health Center, per another obit in the Post-Bulletin. The center also might have contact information about relatives of his, but whether that would include Gene, who knows.
Here's a link to Lee junior's marriage, in case that's helpful.
Lee seems to be in Red Wing; perhaps you are in contact.
Marine-on-St. Croix Minnesota, mentioned on the link below, is a short drive from Minneapolis/Saint Paul.