Firstly, has your friend Reparied Permissions yet? This can be run from
Disk Utility - which resides in Applications/Utilities - it can take a while, but it does help.
If you are not too confident using the CLI of the Terminal, then perhaps download
MacJanitor and give that a run. This essentially does what the computer does when it restarts (I think) - hence the long start-up time your friend is experiencing.
Here's something to check out too: after one slow start-up time ask your friend to shutdown and reboot immediately - maybe the start up process will then be noticably quicker b/c the maintenance tasks and log files have been cleared up.