Weird, why? Since he can't keep this information from leaking around the world, the best strategy is to obfuscate it and show his trusted partners the concepts required to understand it. By gaining notoriety around the world, he is also attracting more partners, and he can filter them out (ie. he knows english, but will only do lectures in japanese, inside the country). If at some point the information gets fully decoded, he will be recognized as having solved the problem anyway. In the meanwhile there is a technological advantage to keep.
What is the technological advantage of proving the ABC conjecture? Seems like any application for it would comparatively take much more time to develop than whatever time advantage can be gained through obsfucation.