GRAGG FUNERAL HOME
PO BOX 400
Binger, OK 73009-0400
Funeral Home Profile
405.656.2313
TURNER FUNERAL HOME
114 N BROADWAY ST
Binger, OK 73009
Funeral Home Profile
405.656.2240

These are the 2 funeral homes they normally most keep good
records and are happy to help the family with information. here is a bit of information I found hope it helps

Name: Earl Howard (Father)
SSN: 448-36-0927
Last Residence: 73048 Hydro, Caddo, Oklahoma, United States of America
Born: 29 Nov 1904
Died: Nov 1981
State (Year) SSN issued: Oklahoma (1954-1955)

This is the son I think burial in the hydro cemetery
Howard Glendon Earl (son) March 12, 1930 June 11, 2004 Hydro Cem.
Howard Opal Lee July 24, 1917 March 26, 2004 Lindsey, OK

do you have any idea of Nina maiden name or another name since Nina is often a shorter version of something.
I don't know if Opal Lee might fit or not but they were the only ones listed for hydro.
Index of deaths in 2004=http://www.rootsweb.ancestry.com/~okcadcgs/obits/2004obits.h... I have not found a trace of this Glendon's father and nina except the SSDi