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... ...