For PhD programs, especially in math, science, and engineering, there is usually full funding given, even to foreign students. That is, they cover full tuition, plus enough money to cover living expenses. Some work – typically grading papers or working in a research lab or teaching discussion sections for first year courses, will be required. Normally, the student will be admitted for a master’s + PhD, and can stop with just the master’s. The financial aid packages are actually usually best at the most prestigious schools, so your friend should just go to the best school he can get admitted to.

Studying Phd is not a popular programme what all students will do.

Getting a admission for students in Phd is purely based on the topic the student choose from.

For a student from China, i suggest him to do it from Hongkong Polytechnic University which is comparatively cheep and more valuable