Hi,
I don't believe that Rudol
f Hess flew a Fokker Dr.I, at least not in combat (a photo does exist of him in front of the Fokker Triplane though). Rudolf Hess' first assignment as a fighter pilot was with
Jasta 35b in October 1918, which had no triplanes.
I think that
Hans-Georg von der Osten would be a good candidate, flying with MvR while with
Jasta 11, and past away in March 1987. Or maybe
Carl-August von Schönebeck, who died in September 1989. I am unsure if he flew a triplane in combat though.
regards,
Darren