What was this “unpublished code”? Something committed to a public git repository where all the code is under GPL? You act as if redistribution of GPLed code was somehow illegal or at least immortal. It’s not. It’s the foundation of the whole idea behind open source.

If that “unpublished code” was stored only on his hard drive and a hacker obtained it illegally, that would be an entirely different topic but that’s completely outside the scope of upstream source code license. That would be an outright crime. Developers at AMD, for example, write Linux driver code for AMD hardware. Then before that code leaves AMD, AMD lawyers need to clear it before it gets published to the Linux Kernel Mailing List for review. Sometimes code is not cleared, so the developers need to rewrite it. As long as the code is behind closed doors, it’s not published (therefore the GPL does not yet apply) but as soon as it’s posted for review, it’s public GPL code and everybody can to everything to it as far as the GPL permits.

This is even spelled out in GNU’s official GPL FAQ. Edit: https://www.gnu.org/licenses/gpl-faq.html#GPLRequireSourcePostedPublic