Fengsuo Zhou said today that Bao Zhuoxuan and two men helping him were taken away by local police from a guest house in a Myanmar border town on Tuesday.
Zhou said the plan was for Bao to meet him in Thailand and then travel together to the United States, where he would study.
Bao is the son of Wang Yu, a lawyer who is one of dozens of rights lawyers and social activists who have been detained or disappeared in China in a crackdown on civil society.