I would first access the integrity of the hard drive, and how it got damaged in the first place. Is it due to external or internal damage, if it's physical or software related, and then go on from there.
If it's software related, like corrupted or deleted files, or something like a corrupted file system, I'd recommend data recovery software: Recuva, ddrescue for a free solution, and r-studio and GetDataBack for a more expensive and reliable option.
If it's physical, like a broken spindle, take the drive to a recovery shop, or if those aren't available, ship it to a data recovery center, and the cost will depend on how much data you've lost.
Best of luck to the dev.