I'd need more information before I could really have an opinion:
I assume there's an all-you-can-eat cafeteria. What's the cost of one meal there?
What's the cost of a typical meal in a pay-as-you-go cafeteria?
Armed with this information, you can figure up how much he might spend in a typical week. Remember that many college students sleep through breakfast.
Is he allowed to have a small refrigerator, microwave, toaster oven in the dorm room? Does his dorm room have a kitchen?
Does he have a car / access to a grocery store?
What's his comfort level with cooking? In other words, will he go hungry before he'll whip up a Steak-um sandwich, or will he have no problem whipping up a simple meal with limited facilities?
If your student "runs out of money", can you add more to his account, or can he pay in cash?
If he doesn't use all his money this year, does it "carry over" to next semester?
Is he good with money, or is he likely to run through his account quickly and need more?
Without having all the information, my best guess is that you should put in a minimal amount, then plan to refurbish it if necessary. I think it'd also be a good idea to discuss with him a per-week allotment. Many college students arrive on campus having had limited exposure to budgeting, and many of them go through the money their parents thought was for the whole year in just a few months. I'd suggest that instead of saying, "You have $1200 for the year", you tell him to look at it as, "You have about $50/week for on-campus food". If he learns this lesson as a freshman, it'll never be a problem again.