Consider the cost of the school for the student, and what the tuition will be. This is the bulk of the student's financial aid, whether or not he lives with his parents.
Add in cost of living expenses. Assess the living expenses based on the general cost of rent off-campus or residence fees on-campus, and food in the area where the college is located.
Assess the student's other financial needs as they may arise, depending on the school. Some expenses you may need to address include buying books, eating on campus, and whether or not the student will need to purchase equipment like a computer. Consider other expenses like health insurance, parking and transportation.