His son could be a lot unhappier

One area where Linux is much better w.r.t Flash than Windows is security updates - you can
ensure Flash and all other apps are updated consistently just by doing 'aptitude update' (or
the equivalent on whatever distro).  On Windows, you have to install Secunia PSI, hope that it
is tracking all your apps, watch for its alerts, then install the updates from each vendor's
site.  And Secunia PSI (which notifies about security updates across vendors) is a very recent
development - until it was released you had to pay for update-tracking software on Windows, at
enterprise price levels.