I wonder if Lloyd Vandeford Sr. was married before Vera and Lloyd and Kenneth were his sons. Then he married Vera and she wasn't equipped to raise three small sons or didn't want to raise Lloyd's first wife's sons.
Also the older Lloyd might have been an uncle or cousin of the boys' father.
Have you contacted Missouri Health and Senior Services Bureau Vital Records and asked about how you can get a copy of younger Lloyd's original birth certificate? You'll find more information about adopton records in Missouri at https://familysearch.org/learn/wiki/en/Missouri
Born: 19 April 1917
Last Residence: Bismarck, Saint Francois, MO
Died: 2 July 2002
Source: U. S. Social Security Death Index 1935-Current
His obituary was published in the Bismarck, Missouri Farm D-J, July 3, 2002.
It's probably to much to think that the younger Lloyd and Kenneth might be mentioned in the older Lloyd's obituary.
Lonny Deloy Vandeford
Born: 16 June 1939, MO
Died: 11 April 1985, Los Angeles Co., CA
Mother's Maiden Name: Kush
Source: California Death Index 1940-97.