There’s a pretty clear difference between the academic caliber and rank of the schools, and as a result, many prestigious companies recruit at Duke and don’t do so at Maryland. I know you said he’s a prospective CS major, but does he have any idea on what jobs he would want? Go on that company’s website and look if they recruit from UM. Go on Linkedin to see how many UM grads work there. It’s not to say that you can’t get a prestigious job from UM, but on campus recruiting at Duke is a huge advantage over having to cold call and blindly apply to many companies.