Seriously, "nobody gives a damn about me" is not a good personal security policy.
No, it's not -- but going to the other extreme is also just as poor a policy as well.
One deadbolt on your front door is relatively acceptable security (much like any Mac computer out-of-the-box). While it's technically feasible and would increase your security, you could also put seven more deadbolts on the door, nail the door shut, and prop a chair under the doorknob as well. What's the result? Increased security! Is it reasonable? Hell, no!
Keeping a good lookout while you're walking across the street is reasonable security to ensure you make it safely to the other side. While it's technically feasible to wear a blast-proof suit while doing so, and would greatly increase chances of survival of being hit by a car, it's just way out of the realm of reason to do so.
Paranoia will make you much, much safer in any situation at the expense of your mental health. No one cares about your Word documents full of family recipes, your travel photos in iPhoto, nor your college essays... there are bigger fish to fry (erm, there are better targets for malicious activity). It has been said that obscurity is no substitute for security, but it certainly helps and most definitely lowers your chances of being hacked and makes the reward of hacking you relatively nil.
If he's worried about someone watching through the webcam, put a piece of tape over the webcam or install the sliding blinder I linked to. If he's worried about someone listening through the microphone, change the sound input to "None" in the Sound pane of the System Preferences.
Without any evidence of active or historical attacks on the computer, there is no reason to go WAY overboard with security. The Mac is secure enough in this regard as it came out-of-the-box. Instead of spending days trying to "harden" my computer, I would rather put that kind of effort into more deadbolts on my front door.