>Abrar Ibrahim, 11, was slowly starving, trapped in one of the most violent pockets of the war until her family escaped and got her to a hospital. Her mother told Dr. Maqdi Seif there was so little food that Abrar eventually got too weak to eat at all.
>Seif took CBS News to see 3-year-old Yussuf Adel, fighting for breath. He has diphtheria, and it can be deadly. A quarter of the patients die.
>"Most of them (are) not vaccinated because of the war," Seif said.
>That's the case here. Yussuf's mother was too afraid of the fighting to go to the clinic.
>Sick as these kids are, most are on the mend thanks to a medical program funded by UNICEF. But there are so many that international aid hasn't reached.
>The Mishkhafa refugee camp is a makeshift village in the barren fields just outside Aden. It's home to roughly 2,500 people who fled violence.
>The Ali family can't get help for their 6-year-old daughter Hannan, who has a serious neurological problem. When she falls and hurts herself, the wounds attract dirt and flies. And there's nothing her parents can do. In a place like this, adequate medical care might as well be on another planet.
>The U.N.'s humanitarian chief has described what's happening here as a major catastrophe and said it has the potential to become the worst situation this generation of aid professionals has ever seen.