Munich has atleast 2 international schools with main language English that are very good - they are expensive but that should be not problem for Kane. He probably sends his kids to private schools in London, too, that should not be really cheaper.
It takes 2 hours to fly to London with a private plane. That should not be a big handicap either to have family over in Munich - or fly back to London for some time. His wife seems to like to go into skiing holidays in the Alps - just takes an hour to do that from Munich. You actually do not need to learn too much German (it is good when you do) to get around as most people understand English.
