Major kudos if they are as wide spread as they sound. I was able to talk with family in Japan using Skype even though their cells were out... so this will definitely help people.
The system was a government requirement for events such as yesterday's quake, but I can't confirm all phone disturbances reported were/are due to it.
Technically, it relies on a bitpattern called "accessClasssNBarred".
My best wishes to your family.
On a tangentially related note, are their hotspots in Japan 802.11n?
Most of them probably aren't. Fonera only has one product that supports 802.11n http://wiki.fon.com/wiki/Fonera_2.0n