Conrad Strughold, after The X-Files film and Season 6

Conrad Strughold was one of the highest-ranking members of the Sydicate that involved the Cigarette-Smoking Man and the Well-Manicured Man and which collaborated with the alien colonists. Strughold seems to be a German national and an influential industrialist. He is likely the founder or heir of a mining conglomerate of some importance in the show, the Strughold Mining Co.

The name Strughold is first introduced in the episode "Paperclip", when Mulder and Scully visit the West Virginia operations of Strughold's company, where files on US smallpox vaccine recipients are housed in old mining tunnels.

Strughold seems to remain strictly outside the US. We first meet him in the (first) X-Files film, where he meets with the other Syndicate members in London to assess the threat posed by the second generation of the black oil (which gestates a biological entity inside its host). At the end of the film, he is in Tunisia, supervising the expansion of the Syndicate's operations in agriculture and bee husbandry.

Given the rapid turn of events in the Season 6 episode "One Son", it is unlikely that Strughold travelled to the US to meet his demise with the other Syndicate members at the airforce base. (Certainly, we do not see him amongst the group that is attacked by the alien rebels.)

I do not believe that Strughold is referred to again in the show.

Is there any information in extended media (interviews, novels, novelizations, comic books) regarding the fate of Conrad Strughold?

In Season 7, we see the Cigarette-Smoking Man's attempts to rebuild the US side of the Syndicate. Given Strughold's resources, one can imagine that he continued his work abroad. But what became of this, especially in light of the rise of the "supersoldiers"?

We also learn that Alex Krychek was eventually captured in Tunisia, after his divergence from the Syndicate in "One Son". Was he working for (or against) Strughold prior to his capture? One can also imagine that the Smoking Man sent Krycheck overseas to undermine Strughold's operations.