It might be older because many companies made detectors in this configuration back in the day.
More probably it is something like this one, a GC-1006 "Professional" Metal Detector.
Cheap plastic Chinese junk based on old outdated designs and sold to the ill informed.
If products like this work at all most of them don't work well.
Might make a good doorstop with some modding, as far as worth if he is looking to sell it, not much.
Things like this are not worth much when they are new and that one looks broken and abused so...