Honestly, I would not buy them, for multiple reasons:

They’re out of print and only available used, so no more money would go to the copyright holders than if you simply pirated them. The only people who win are the price gougers who sell them to you for way more than they’re worth. In a way I think it may be slightly less ethical to buy them from these people, who are out to take advantage of you and others, than it is to download superior restorations done by dedicated fans who aren’t looking for a profit.
They are of pretty bad quality. They are watchable, and I made do with them for a few years before I discovered Despecialized, but now I can’t go back. If you own a widescreen HDTV like most people in the 2010s, they will not look very good on it. It’s an old grainy transfer in 4:3 letterbox, not anamorphic widescreen. Doesn’t look that much better than the laserdiscs sourced from the same masters.

That said, I’m glad to read that your son has done his homework and is more interested in seeing the film cuts with real historical value over butchered cuts with bad CGI. That’s an encouraging sign. And you really should get Despecialized for him to reward him for it, with the added benefit of considerably less taken out of your wallet. They take the best sources available for each scene and correct the colors to match the films as they were in theaters as close as possible, more so than the DVDs do. In some cases those are actually upscaled versions of the DVDs. The work of getting the most out of them has already been done for you. No reason to stick with the DVDs themselves.