GREENWICH - For most people, Mother's Day is synonymous with flowers and fun, but this year's holiday has offered one Greenwich couple a special opportunity to help mothers in their native Japan.H Kuwana and his wife, Yumi, will travel to the tsunami-ravaged country this week to lay the groundwork for a private relief effort to help thousands of widowed mothers struggling to rebuild their lives after the disaster that struck their homeland two months ago.Thanks to the help of donors like Sara Herbert-Galloway, of Greenwich, the Kuwanas have raised hundreds of thousands of dollars."It makes me feel good to know that I can help people in some way, no matter how small it is," Herbert-Galloway says. Herbert-Galloway is working with the Kuwanas to help organize a star-studded charity event on June 18 featuring former Mets manager Bobby Valentine.