What state are you in, and is this in the US? If it was a dorm shake down, it was most likely campus police. Different states differ in criminal penalties for marijuana possession, and charging for marijuana sales is getting harder for the "police" is SOME areas of the US. This last year there has been ground breaking reform for pot laws all through the country! So, in short, yes, he could possibly and likely! be only arrested on misdemeanor charges!