His phone is on Android 8.1.0, an LG Stylo 4. I installed an app to do it but it only offers backups to One Drive, Drop Box, GMail (iirc) or SD card. He had none of those. So I would prefer not to take any of those paths, particularly without knowing if the saves were even usable on a PC.
How can I do this, preferably via USB to the PC and preferably for free? The saves need to be human readable; I only mention that because I recall from a distant past, extracting text conversations from a Windows phone and the date/time stamps were the seconds from some fixed earliest start date.