Thing is he's seeing the same issues with other networking devices. I had him try reinstalling the phone tethering USB driver, but that didn't work either (although I don't recall getting a confirmation as to whether he had tested the phone tethering with another laptop/desktop to eliminate that as a confounding issue). So it's rather odd from that point of view.That sounds like a jank wifi-chipset and as usual I suspect VIA. If it is drivers issue and he have drivers that work stored locally, then install those manually. 1903 or whatever it was fucked over my PCIe USB card with newer drivers but I had the working cat/inf so it was trivial to replace.
Honestly, just getting a pirated Win 10 or 8.1 installer off some torrent is probably the best option.