If he's using multiple partitions and actually changed the partition boundaries (in the RDB), it's very tricky going backward, short of carefully replacing the old RDB settings, which I doubt were recorded anywhere. There are tools on Aminet (maybe RDBSalv ?) that hunt for missing partitions or scrambled RDB's, but I've never had to use them and can't say how well they work. If he performed a complete, full format of any partition, that's a complete dead-end. On the other hand, if he performed a quick format on any partition, or a partial full format, these can be reversed by Disksalv 4 (with varying degrees of success), assuming you have a copy handy.
It's probably worth asking if the time spent from all this recovery work is better spent reinstalling the OS from scratch. You may still be able to salvage important files with Disksalv, Quarterback Tools, etc., without actually recovering the partitions(s), assuming you can find somewhere to save the files...maybe a 2nd floppy drive? Next time around, he'll treat HDToolbox with a little more respect. ;-)
Hope that helps,
Todd
