I'm not sure that he is suggesting it, but it is a reasonable worry. Not in the near term of course, say over the next 20 years or so. Within that time frame, a war within Europe is almost unthinkable. However, combine the geopolitical situation in Europe with a new generation or two for whom the disintegration of the Euro is the defining event in their perception of Europe, and mindsets will change.
In the face of declining European integration, our best long-term hope against wars would be the declining size of populations combined with a relative dearth of resources. Some people are hopelessly optimistic that this is enough, but I personally wouldn't count on it.
Any war-related worries one might have if Germany leaves the currency union or the EU should also apply to Norway [edited] and Switzerland (not in the EU at all), as well as the UK, the Czech Republic and Hungary (in the EU, but not Euro nations).
So is a war between the Czech Republic and Hungary, or Finland and Sweden a reasonable worry over your 20 year timeframe?
In the face of declining European integration, our best long-term hope against wars would be the declining size of populations combined with a relative dearth of resources. Some people are hopelessly optimistic that this is enough, but I personally wouldn't count on it.