A speech at Gonzaga University by Robert F. Kennedy, Jr., Thursday to help raise money for two environmental organizations was indefinitely postponed Wednesday. Spokane Riverkeeper and Lake Pend Oreille Waterkeeper, the sponsors of the event, said in a press release it was postponed at Kennedy’s request to deal with a “private family matter” which was not further explained. The Associated Press reported Tuesday that Kennedy’s wife, Mary Richardson Kennedy, was arrested Saturday for drunk driving after she ran over a curb at a suburban school in Bedford, N.Y. Details on a rescheduled event will be released as soon as possible, a press release for the organizers said.