From his death record it indicates his SSN was issued in South Dakota, which led to many results on familysearch.org. Some examples are below. You should try their free search tool at https://familysearch.org/ and plug in his parents/siblings name to find more.
The father of this Paul R, Winford O b. abt 1878 MN appears to be the son of Lyman b. NY and L E (Ellen) b. MO. More confirmation needed, but a good place to start.
I put a few examples below.
United States Social Security Death Index
Paul R Wilcox
birth date: 22 May 1923
social security number: 503-22-0497
place of issuance: South Dakota
last residence: King, Washington 98028
death date: 25 February 2003
estimated age at death: 80
https://familysearch.org/search/records/index#count=20&query=%2Bgivenname%3A%22paul%20r%22~%20%2Bsurname%3Awilcox~%20%2Bbirth_place%3ASD~%20%2Bbirth_year%3A1922-1924~
US Census, 1930 Township 06, Meade, SD
head Winford Wilcox M 52 MN/NY/MO
wife Ilene Wilcox F 31 SD
son Warren O Wilcox M 12 SD
son Lloyd Wilcox M 10 SD
dau Ida D Wilcox F 8 SD
son Paul R Wilcox M 7 SD
son Elmer Wilcox M 4 SD
son George A Wilcox M 1 SD
Earlier census searching Warren
U S Census, 1920, Meade, SD
self Winfred O Wilcox M 42y MN
wife Ioleen Wilcox F 20y SD
son Warren Wilcox M 2y S D
son Lyod George Wilcox M 4m SD
If you plug in Winfred O Wilcox b. 1878 MN – you will find one whose father was b NY mother MO. Winfred O is on several consecutive census, here is just one.
Minnesota, State Census, 1885 Sioux Valley, Jackson, MN
Lyman Wilcox M 50y NY
L E Wilcox F 27y MO
A A Wilcox F 9y Minnesota
W O Wilcox M 7y Minnesota
L G Wilcox M 6y Minnesota
O A Wilcox M 4y Minnesota
M E Wilcox F 1y Minnesota
