Ancestry.com https://www.ancestry.com/search/collections/1174/ has passport applications issued from 1795-1925 and US Consular Post Applications 1915-1926, so you should be able to find his application in these records.
Familysearch.org has the same applications https://www.familysearch.org/search/catalog/500311?availability=Family%20History%20Library
Dear Ms. Art,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the Consular Registration Applications, 1916 - 1925 in the General Records of the Department of State (Record Group 59) that contains two types of applications for registration filed at U.S. consulates and legations, one for native-born and one for naturalized citizens of the United States intending to remain in a particular country for an extended period of time. These records have been digitized and are available using the Catalog. NARA’s website Passport Applications also may be useful for background information about the passport process.
We hope this is helpful. Best of luck with your family research!