Thread moved to correct forum. Does not belong in "Images........"
Unless you were making backups of your hard drive with Time Machine or some other backup software, you can not restore anything without using expensive recovery software. And the chances of recovery software working is slim if you used the computer after he deleted them.
Even if you were using Windows, you couldn't restore photos that were deleted because the Windows System Restore function does not backup documents, photos, data, etc.
If you wish, you can try to recover them with
Data Rescue 3. You can download a trial version to see if it will work for you. If it does, buy a license. ($99.00)