Drupal, Joomla or Xoops?

I made a simple static HTML website. Now the client wants to be able to update the site himself. Basically, he wants to edit the contents on “Events” and “Jobs” page on a regular basis - weekly. Everything else on the site remains static.

My question is: Do I have to use Content Management System to build it so that someone who doesn’t know HTML can make changes on a regular bases? And if so, how do I begin? I know nothing about CMS. :frowning:

Which CMS is better? Drupal, Joomla or Xoops? (I am looking at their sites right now.) How difficult are they?

I don’t want to rebuild/convert the site to CMS. I would like to rework only the “events.html” and “jobs.html” pages. Is that possible??