Recommendations for an OS to install on an old Mac laptop?

<p>A relative owns an old Mac laptop, a MacBook Pro 5,5, that is used as, basically, a Chromebook: to run Google Chrome to run Google Docs and other Google Web apps. The laptop runs Mac OS 10.11 and cannot update further. Its Google Chrome is stuck on an old version, 103.0.5060.134, because newer versions no longer support Mac OS 10.11. As of recently, Google Docs says it no longer supports this laptop's old version of Chrome.</p> <p>The laptop’s "About This Mac" function links to (a URL that redirects to) <a href="https://support.apple.com/en-us/112474" rel="ugc">this page of hardware specifications</a>, which calls this model of laptop “MB991LL/A”. The laptop reports that it has been upgraded to 8 GB of RAM.</p> <p><strong>Is there an operating system that people here would recommend that</strong></p> <ul> <li>would allow this computer to run, <em>preferably</em>, a modern version of Google Chrome, or <em>at least</em> Chromium or Iceweasel or something else capable of running Google Web apps, and</li> <li>is likely to support such an old computer for at least the next, say, 5-10 years?</li> </ul> <p>The owner of the computer has, I think, negligible experience using non-Apple operating systems and no experience using non-commercial operating systems, but I am reluctantly willing to serve as tech support rather than let the computer become useless.</p> <p>I am unfamiliar with BSDs other than Mac OS (and I haven't used that since it was “Mac OS” rather than “macOS”), but I was wondering whether FreeBSD would be a good choice, not only because it is a distant cousin of Mac OS but because I have an impression that it moves more slowly than major Linux distros tend to.</p>