Not to defend the Nazis in any way, but that sounds like abandonment.
Maybe they were out of the country and the Nazis just confiscated their property. Maybe the family figured it was unsafe to go back. Maybe they had to give up everything they owned to get out.
By now, international law probably recognizes that if you're, say, a Rwandan who leaves the country in fear for your life, you haven't abandoned what you left behind to the government that threatened you.
If a government says you can't leave the country without surrendering your property, that looks like an infringement of basic rights of movement and ownership.