There is a giant difference in helping the jw's in 3rd world countries when they experience a catastrophe and jw's in an industrialized country like the usa. 3rd world residents are usually ecstatic just to have a roof put back over their heads and enough to eat. Usually those poor people in 3rd world countries end up with a better place to live if their shack is destroyed. So in those countries, 'volunteer' workers are more than sufficient.
More affluent countries where jw's live expect much more when a catastrophe strikes and the clean up and rebuild begins. I've been to Houston and I know jw's around there. Many live in very luxurious homes so I don't think they will be welcoming 'volunteers' to repair and rebuild their homes.
just saying!