hello sir, 

to get admission, he must clear the TOEFL/IELTS/GRE exam however, GRE would be best as it also helps you to get some financial aids while studying abroad and then with the marks he can apply to the colleges. 

now different uni abroad look for different scores from the student, experinces and letters of recommendations as documents while applying. 

https://university.careers360.com/articles/five-minute-guide-toefl-ielts-pte-gmat-gre-sat

THIS link might help you know more.