(CBS News) In the towns and villages around Aleppo, Syria, the streets are eerily quiet.
Dr. Maher Nana left Syria 13 years ago for the United States. Now he is in Aleppo trying to organize rebel forces.
"The town is totally different," says Dr. Nana. "People have deserted. Whoever left here, they were living under bombardment."
The psychological toll on residents has been staggering.
"Kids cannot sleep at night. People -- they're, they're just expecting to get hit at any time."
Dr. Nana runs a family practice in Delray Beach, Fla., but now spends much of his time traveling in and out of Syria on behalf of an organization called the Syrian Support Group. Its goal is to transform the Free Syrian Army from a disorganized grouping of militias into a coherent force. But it also works closely with the U.S. government to identify credible rebel officers and report on their progress.
"These commanders, they vow to protect civilians," Dr. Nana says. "They vow to protect democracy. They vow to obey international laws."
Making vows is easy. Sticking to them is much harder. But Dr. Nana does his best to ensure the commanders respect human rights.
"You provide and you check and you provide and you check and you provide and you check. And you make sure that they are standing for their values," Dr. Nana says.
To see more of this report from inside Syria, tune in to "60 Minutes" on Sunday night.