... the chance that he could get a PhD just for this?

A Ph.D. in what? The subject matter fits into some odd interdisciplinary combination of Philosophy, Economics, Operations Research, AI/CompSci, and Statistics. In general, the research requirements for a PhD in CompSci are roughly equivalent to something like 4 published research papers plus a ~200 page dissertation containing material that can be worked into either a monograph or another half-dozen publishable papers. But there are other requirements besides research, and many institutions don't like to allow people to "test out" of those requirements because it looks bad to the accrediting agencies.