It doesn't sound like he's necessarily taking the place of anyone. I don't smell a lot of grant money in this kind of research, nor do I see a lot of equipment or lab space being required.

And, yes, research has value. If this fellow writes down what he knows, and what he finds out, people in the future will be able to read it. That's creating something of value. Would it be better if this hundred-year-old smart guy took all his knowledge to the grave?

Nowadays it's fashionable to think of all education, right up to the Ph.D. level, as a kind of jobs training program, but in fact the traditional point of the Ph.D. isn't to make yourself smarter. It's to make the world smarter by doing some original research and then publishing it.