Were these recorded with a DVD Recorder? Probably never closed the burn on the discs so they are 'open' and that gets funky with drives that didn't burn the disc in the first place.
Data Hoarder
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
That's pretty much what it is. I had one of those DVD DVRs back in the day, and they never finalized discs by default since the idea was that you'd mainly use them with the DVR itself, and the device can't know when the right time to finalize is.
The 'correct' way to fix it would be to find the model of DVR used to record them and finalize the discs, but that's pretty unlikely unless the seller also had the DVR on hand. I don't know if there's any regular burning software that would know how to do this.
You could try another optical drive? Maybe another brand. Could be the laser it's using and the disks may have faded, and another drive might work.
They should definitely try another drive, preferably a DVD burner.
Also depends on the color of the bottom of the disc. Lighter colored discs (like yellow) are cheaper quality and can be more difficult to read. Darker blue or purple "azo" discs are better for long-term data storage.
I'm so curious. How much was the box?
Disc rot is exceedingly rare. Maybe you will find one or two in a box of a thousand perhaps.
What is very likely is they never finalised the discs. They will/may be able to be finalised in a dvd recorder.
Without finalisation there is no valid filesystem thus they appear blank.
When I get home I'll give this a go, I usually use RW discs in my recorder, which ensures I dont need to finalise.
Probably recorded from TV using a DVD recorder and the discs were never finalized. If you can find a recorder by the same manufacturer you may be able to finalize them and rip them.
This thread mentions a handful of other tools that might work and are cheaper or free: https://superuser.com/questions/148647/how-to-read-old-non-finalized-cds
Get an LG DVD drive
Could you check if your local library has a media centre? That might be an easy option and they might support weirder file formats
We have some like this, but I've yet to try them: https://www.vpl.ca/facilities/digitize
Librarians are also good about archiving information, and they might be able to point you in the right direction.
I'd still try IsoBuster in free mode to see what it says !
If it too says the discs are blank then you need to try different hardware because it then means your disc drive sees the discs as blank (and as a consequence won't read from them)