If he's messing around in Compiz, it's also possible that he's stumbled on some combination of visual effects which broke the compositing window manager. Try going into System -> Preferences -> Appearance -> Visual Effects, and select None. If you get your title bars back, then try turning visual effects back on and see if it resets things to a sane state.
Compiz still has some rough edges. I generally leave the visual effects disabled on machines I use for real work, since it tends to break the VNC client (among other annoyances).
If the world isn't making sense to you, you're either drinking too much or not drinking enough.