I don't know anything about The Muslim Issue, but it reports "migrants" are passively moving into Afghanistan. Once numbers are sufficient, they're said to be rising up, deposing the local Taliban, replacing it with ISIS aligned factions.
Would love to see any reporting of similar accounts or claims.
I have seen reports, however, that Afghans are now exiting their country in droves, making their way to heart of Europe, much like the self-labeled, oft suspiciously labeled Syrians.
Someday, nations are going to wake up, and realize the concept of having enforced borders was a great idea after all. But it's also likely they'll be hopelessly overrun by the time they do. We may be there already.