Old Apex theme packages on the Play Store from 2015–2017 still work. Search for “Apex theme” and test free ones first.
Apex Launcher 4.0.1 APK Download: The Classic Customizer Gets a Final Update Apex Launcher 4.0.1 Apk Download
He opened the file. His phone gave a security warning about "Unknown Sources." Old Apex theme packages on the Play Store