I'm curious (having some basic German) what's wrong with the German examples? Isn't most of the German taken from the article he is responding to?
edit - actually I think I see it - he's not inflecting the articles correctly after "von"?
edit - actually I think I see it - he's not inflecting the articles correctly after "von"?
Anyhow, in German, you can use the Saxon genitive in preposition, if the word in Genitive can be used like a personal name: "ich sehe Karls Auto". And it is true that you cannot recurse on that: "ich sehe Karls Bruders Auto" is not German, except maybe in German poems two hundred years ago, when the language was raped. Even "ich sehe meines Vaters Auto" will sound outside of the norm.
However, you can recurse in postposition: "ich sehe das Auto meines Vaters", "ich sehe das Auto des Bruders meines Vaters". You do not have to say "ich sehe das Auto vom Bruder von meinem Vater".
Several edits, sorry.