> The code is GPLed[1]. It sounds like there were other people willing to contribute. The code goes on, without him.

That's not how it works - other people are free to fork the code, but the trademark is owned by the original author.

This is one of the reasons why open source foundations exist - they hold the trademark and decide on how it can be used. For instance, CNCF or Apache Foundation holds the trademark for its member projects - you can't call your Prometheus fork "Prometheus" and use their logo etc.