My concern is over his home machine being cracked, not the
school administrators. If they want to be idiots, they will
be idiots no matter what he does.
There is some truth to what dws says, far too many school
officials these days seem to be petty tyrants and really
don't like dealing with kids who can show them up. But
still if you are connecting to your machine over the net,
there are good reasons to use ssh rather than telnet.