I've been to Germany. His collection lives on the top floor of a modern and very well protected office. 24h guards (some old Leibstandard Adolf Hitler guys), acces with keycards only, crocodiles and Panzer tanks around the building, some Messerschmits flying over 24/7, of course lots of concrete. Rumours say his office is build bij mr. Tödt who also designed the Atlantikwall. But like i sayd: Rumours only.
But what's even worse: His collection is constantly surrounded by a bunch of German top lawyers.... You won't go in there voluntary!