Don't say to the kid that he wasted a year of his life. He most certainly did not. What I think he really accomplished is a successful (if not practical) intellectual exercise. Using technology in ways that the original creators of that technology did not necessarily intend is something to be applauded when the intent is for the good.
However, the main problem I see with this sort of 'invention' is that it has a lot of problems that were not addressed. Likely they could not have been addressed. (Yes, I know this was done by a 7th grader and was way more awesome than anything I have ever done, so let it be said that what he accomplished was great, ok? That it was great is not the issue.)
My wife is blind and has struggled with using adaptive technology for the last 35+ years. She has used just about every type of adaptive media device (screen reader, talking note takers, braille printers from a PC or standalone manual ones, etc.) available. I have learned from her that not every "adaptive" technology or device is practical to use, regardless of cost, and for many reasons. Most, even the best funded ones, the ones blessed with loads of well-intentioned R&D, are not practical. To say nothing of cost......
What does seem to work best (though usually not as well as hoped) is adaptive technology that builds upon other existing tech without basic gaps in the steps from "need" to "satisfaction of that need in a practical fashion".
For example, the printer prints braille. This is a great, basic concept that would at first-glance seem to satisfy a basic need, except for the fact that there is at least one major adaptive "gap" present. The end-user has to use a non-adapted controller to process the text or just to make the printer print. Then there is the issue of how to get the data you want to print to the printer. My best hope is that this is done via the custom software that programs the printer. Is that software accessible to a blind person using the computer which runs the Mindstorm software? One of the most popular screen-reading software packages is JAWS (Job Access With Speech). It's pretty much the best out there. But it has several problems, too. It's expensive (several hundred USD). It doesn't work great with every piece of software, and especially not with custom software that doesn't adhere to Windows-types of GUI design patterns. So can it work with the printer's custom software? Maybe, but experience tells me it likely would not work well, if at all.
(Of course, there are other practical issues with the printer that I can't fault the kid for not being able to address since he has to work with what he's got. Mindstorm kits are flimsy at best and tend to fall apart. The printer is slow. The battery is short-lived. It prints on non-standard paper which is not practical to store or walk around with in bulk, which is what you get whenever you print braille on paper- a typical novel printed in braille weighs like 12-15lb and takes up a volume of approx. 4x "6x12x12" inches, with the Library for the Blind cases)
So, while the kid's invention is very, very cool, it is just another example of technology created without adequate input from experienced end-users of the adaptive product. This is a very big problem with the adaptive device industry as a whole. I can't tell you how many very expensive, professionally produced adaptive products my wife has bought or, luckily, demoed without cost, only to find that while the intent to provide a practical, useable product was there, the producing company ended up making a tool that was woefully not up to the task, or if it did do things adequately, it was not practical to use (too large, too heavy, too slow, too buggy, too prone to breaking or too expensive to fix).
An example of a good adaptive software / device combo is Apple's "Voiceover" software that comes bundled with iOS. While not perfect, and while much of its suitability-to-task depends on app programmers sticking to certain design patterns, it is good enough of a tool that my wife can largely eschew use of her PC. using Voiceover on her iPhone has opened up a whole new world to her. And Voiceover is absolutely free, once you buy the iPhone.
I'm hoping the kid someday lands a job with an innovative tech firm and makes products that are better and cheaper than the ones blind people have to depend upon today. Good on him for trying!