What would be more impressive to me and practical would be spending time contributing to the Linux kernel. That is something that companies would more likely be interested in.
This is kind of dismissive, mean, and misses the point. It's like watching a person make 100 free throws in a row, then saying you'd be more impressed if he go into the NBA. It's an order of magnitude more difficult to make a meaningful contribution to the Linux kernel, so of course it would be more impressive.
Any contribution that is kept is meaningful.
He could start by taking the Eudyptula Challenge: https://www.linux.com/blog/learn-how-contribute-linux-kernel...
Or he could read one of the many other resources out there about how to get started: https://www.linux.com/news/three-ways-beginners-contribute-l... https://kernelnewbies.org/ https://www.quora.com/What-is-the-best-way-to-start-contribu... https://www.kernel.org/doc/Documentation/development-process... https://www.kernel.org/doc/Documentation/SubmittingPatches http://helenfornazier.blogspot.com/2015/06/linux-kernel-how-... http://ozlabs.org/~rusty/Stupidity.html http://stackoverflow.com/questions/4576332/i-want-to-contrib... ...