I'm getting a heartbreaking number of hits from people looking for their brothers in Haiti. My brother, who is in Haiti, emphasized when I spoke to him that it does not mean someone is injured or dead if you can't reach them. But it is extremely difficult for people to make contact. Try Skype if you can: He was able to get through to me that way when nothing else worked. Remember that without electricity, people can't charge their cellphones (or computers).
I know exactly how it feels to not know if your brother is okay. I can't begin to say how much I hope you find your brother alive and well.