Board Thread:Theories and Speculation/@comment-31074250-20170318090411/@comment-25122992-20170429200707

Well, he knew it the same way as he learned about Boruto's "future", which hasn't been explained yet, but it seems some kind of a Byakugan ability (since he activated it in both cases). And there can be a plenty of reasons why Naruto cannot pass his power to someone, starting from the fact that not every human is compatible with tailed beast like Kurama, who is one of the cornerstones of Naruto's abilities, and ending with the simple logical conclusion that Naruto isn't Hagoromo and cannot grant his advanced abilities like SPSM to someone else. The best thing he can grant is Kurama's chakra and thus the chakra shroud, yet all we know that this chakra is pretty much expendable.