Margie:

You wrote that your brother called you via cell phone before. Even though his cell phone worked for that one call, it may not work again for a while, possibly hours or days, and it may not work in specific areas during or after the storm. So I would not lose hope based on the fact he hasn't called you again; even in much weaker storms, cell coverage becomes very spotty. (If you need an example, here in Miami cell coverage still isn't 100% after our brush with a very minimal cat 1 version of Katrina, and I only got a few calls out to family - despite hours of trying - in the first 2 days after the storm.)

I certainly wouldn't give up hope, particularly based on the fact you haven't gotten another call.