First you need to find what he wants to study and then find appropriate university and apply He might also need to appear for English proficiency exams like ielts, toefl and gre All these depends on the each university's individual requirement and what he wants to study. And then he will need to apply for a Visa at a local us consulate general and face a Visa interview. Usavisatraveldocs website might be helpful
Ask them but you may need to consult a immigration lawyer for advice.
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