Dear Mr. Holtz,
Thank you for posting your request on History Hub!
Service can be verified by requesting a copy of his Official Military Personnel File (OMPF). OMPFs for those who served in the U.S. Armed Forces and who were separated from the service before October 2002 are in the custody of NARA's National Personnel Records Center (NPRC) in St. Louis. In many cases where Army and Air Force personnel records were destroyed in the 1973 fire, proof of service can be provided from other records such as morning reports, payrolls, and military orders, and a certificate of military service will be issued. Navy and Marine Corps OMPFs were not affected by the fire. Please complete a GSA Standard Form 180 and mail it to NARA's National Personnel Records Center, (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002. If there is any information requested by the form that you do not know, you may omit it or provide estimates (such as for dates), but the more information you provide, the easier it will be to locate the correct file if it survived the fire. For more information see Official Military Personnel Files (OMPF), Archival Records Requests.
Military personnel records are completely opened to the public 62 years after the veteran leaves the military. If less than 62 years have passed since the veteran’s discharge date (to include any reserve time), certain information in the records is not available to the general public without the written consent of the veteran or his next of kin. For more information see Request Military Service Records and Official Military Personnel Files (OMPF), Archival Holdings.
Due to the COVID-19 pandemic, NPRC will continue servicing requests ONLY associated with medical treatments, burials, homeless veterans seeking admittance to a homeless shelter, and those involving the VA Home Loan program. Please refrain from submitting non-emergency requests until NPRC returns to pre-COVID staffing levels. Please check archives.gov/veterans for updates to the NPRC operating hours and status. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful.
You can also submit a FOIA request in order to get some basic information on a veteran. It might take a while since the NPRC is only doing emergency work right now.
You could try contacting the state he served if he was (NG) National Guard. Find out unit he id in or served and find out if the timeframe matches deployment of that unit.