Dear Ms. Thompson,
Thank you for posting your inquiry on History Hub!
We searched the National Archives Catalog but were unable to locate any records relating to the 35th Naval Construction Battalion.
We suggest that you review the website of the U.S. Navy Seabee Unit Records section of the Naval History and Heritage Command (NHHC) for a report about the 35th. We also suggest that you review the SeaBee Museum for additional information.
We hope this is helpful. Best of luck with your research!
Have you requested his Official Military Personnel File? See here for instructions: https://www.archives.gov/personnel-records-center/military-personnel/ompf-archival-requests
Also, there might be records for his unit in the file Shore Establishments, Construction Battalions 30-49. The catalog description gives the point of contact for these records.