The witnesses take care of their own first. But I've heard many stories of charity to outsiders as well, but admittedly not at all on the scale of other churches or charities.
AND it's all done on a local level. While Brooklyn Bethel asks that all monetary donations go straight to the World Wide Work, they expect the local congregations to take care of the actual needs of the victims. So, in addition to putting money in the contribution box, a local publisher would be asked to donate time, more money, labor, materials to the victims. And Brooklyn Bethel sits back, makes their fat little deposits in the bank, and issues periodic "look how nice we are" press releases.