http://j1visa.state.gov/programs/summer-work-travel
The Summer Work Travel program provides foreign students with an opportunity to live and work in the United States during their summer vacation from college or university to experience and to be exposed to the people and way of life in the United States.
他应该回国。这个签证应该是和雇主链接起来的,好比H-1 work visa,没有工作就没有签证。