Santa Barbara, California, July 23 -- The last text message from Jean arrived on April 26.

The severely underweight 20-year-old man with diabetes wrote to Alfred Kakisingi on WhatsApp to say, once again, that he could not find enough food.

Jean, a pseudonym used because his family could not be reached, required insulin. According to Kakisingi, manager of the Goma-based Association des Diabetiques du Congo, or ADIC, Jean's mother had almost no income and his father opposed the treatment because he believed a traditional healer could treat Jean more quickly and effectively.

"His father formally prohibited him from taking insulin," Kakisingi said, forcing Jean to inject himself secretly, often in a bathroom.

Kakisingi had been helping Je...