If you're wanting multiple access/editing capabilities, you can do some
serious database stuff with MySQL
http://www.mysql.com/
For what he is doing, MySQL would be overkill. Access or FoxPro would
be his speed (although of course OT here). Installing MySQL is
non-trivial as well, at least on Linux - Windows is probably much
easier.
I've seen people try to do tasks in spreadsheets which are better
suited to a database before. Generally, if you're really good with
the "database emulation" features of a spreadsheet, you might get by
with it, but usually it's easier to do a database. The one area where
it may not be easier is customizing a report from the database. A
good report writer like Crystal Reports can handle most needs, but it
is sometimes not trivial to get reports out the way the users want
'em. On a spreadsheet you can manually muscle the rows and formulas
around to get what you want visually, so to speak, which is sometimes
easier than defining a report with complicated control breaks and the
like. But usually data editing features and such on spreadsheets are
less capable than what a database can do.
In his case, the requirements seem to call for a database, but he
probably could get by with a spreadsheet with some moderately
sophisticated approaches (maybe multiple merged sheets or something to
allow for multiple users, that sort of thing.)