If he has any important data on the hard drive, I wouldn't recommend attempting to turn on the computer or running any further disc utilities. That could cause further damage to the hard drive, which will make it harder to recover any data if he decides to take the offending hard drive in to a data recovery service. (Sadly, I speak from experience here.)
If he doesn't have any important data on the drive or if the data is backed up elsewhere, then there wouldn't be any harm in trying additional measures to boot up the computer... The worst that could happen is that the HD totally craps out, but it sounds like it's almost there anyway.
If he's near an Apple Store, it would be a good idea to bring it in.