Last time I checked, he was currently in charge of much of the SEAL H2H and CQB training. They hold him in very high regard, and are very quiet about what goes on.
I've looked around a bit, and I can't find anything on what he does--other than his system is allegedly loosely based off of Fukien Wing Chun
. But don't quote me on that, because I am not sure that it is anywhere near the truth.
Fact of the matter is that our SF guys don't engage in unarmed combat that frequently. Hell, if they do, they're probably in very big trouble. I'll bet they're tough guys period, but hand to hand undoubtedly comprises a relatively small percentage of their training. Dieter must have something to him if he has stuck around this long, though.