That sounds reasonable considering that most of the money is in labor and not parts. Its not a small undertaking especially with those cars. I am a tech at a honda center myself, I agree 100% with the timing belt and water pump, the only time you know a belt is bad is when its too late. In terms of book time when you add in the water pump/timing belt its not that much more because you are already removing the parts to begin with. I do not recommend taking the car to a community college though, as this job requires that the camshafts and timing gears stay locked in sync otherwise you take the chance of bending valves.
Being a 2008 if he has never had overheating problems it could be a problem with the antifreeze and if he is changing it at the intervals, kind of rare and not normally an issue but the antifreeze that Honda uses is spec'd at 5 years/60,000 miles, even though civic manuals say 120,000. To test a head gasket, the mechanic will usually start the system, get it hot, then connect a hourglass like tool to the radiator where the cap goes, It has blue dye in it that reacts with flammables in the antifreeze, changing the color of the dye. The system is under pressure when this happens so usually at that point the radiator is usually checked.
Good luck to you and your buddies ride, they are tanks when properly maintained and I have seen them with 300k+ miles (not the best lookers/smellers but gets the job done).
