This obituary for his son from the 11 Aug 2019 Cincinnati Enquirer lists his son's relatives.
Cincinnati - Jenike Sr., William F., loving husband of Jewel nee Penn Jenike for 70 years. Devoted father of Janice (David) Jacobs, Judith (Harry) Hadden, Martha Joanne "Jody" Jenike and, William "Bill" (Lisa) F. Jenike III. Adored grandfather of 10 and great-grandfather of 17. Beloved brother of Dr. Joseph Jenike of Dallas, Texas. He is also survived by numerous nieces and nephews. Passed away on Thursday August 1, 2019 at the age of 88, surrounded by his family and wife. Memorial Donations can be made to VITAS Hospice, 11500 Northlake Drive, Suite 400, Cincinnati, Ohio 45249. Funeral arrangements handled privately by the family.
A website, such as familytreenow.com may help you find the address or phone number (less reliable on search sites) for a family member.
Dear Ms. Miller,
Thank you for posting your request on History Hub!
The National Archives and Records Administration (NARA) does not provide services to locate living individuals. The records in the custody of NARA were typically transferred from other Federal agencies at least 20-30 years after they were created and used. Therefore, NARA records are not usually helpful in providing current information about individuals. Please review NARA’s Locating Veterans and Service Members web pages for some ideas.
We hope this is helpful. Best of luck with your research!