He can do what I do with my own personal projects: if you install something I wrote, you get the source code whether you want it or not. Setup.exe basically dumps a copy of my development directory into the specified installation folder.
That way, if I get hit by a bus, it's fine, The Source Is Out There. If someone wants to send a bug fix or improvement, great, thanks, I'll be glad to take a look. Otherwise, don't bug me.
The idea that "open source" is necessarily a full-time maintenance job with formal processes and expectations is something somebody made up.
