if he's changed the pads and discs before then all he's got to do more is unscrew the flexi hose, piss easy.

he should clamp the hose first to minimise fluid loss and he'll probably find he has to unscrew the caliper from the hose as the hose end doesn't twist (well it doesn't on my focus anyway) and he might have to slacken the hand brake cable a bit but its easy.

while he's at it he may aswell change the brake and clutch fluid, only way to do it in my experiance is to get a gunsen eezybleeder as you won't bleed the clutch by pumping the pedal. easy job to do as you fil the bottle then go round the bleed nipples one at a time. he'll prob need to refill it though half way through. oh by the way it leaves the reserviour brim full so it'll need to be emptied a bit, i usually empty the eezybleed bottle and reconect it and bleed a little out a nipple.

hope that helps i'm sure he'll be fine.