wouldnt it depend though on if he did a quick format or a full format? I don't have any experience with file recovery software but doesnt a quick format work the same as just deleting the files in windows and the full format actually overwrites the data?
the way that software works, at least the most recent versions that ive tested, it will recover files from a current partition, or a previous partition that was written over. Data recovery software has become more powerful in recent years especially to be able to recover data from previously destroyed partitions.
having said that he still has a way better chances of finding those few files he wants if the drive was only quick formatted, and no new data has been written since.