Yeah, best to buy a laptop on what he needs it for. Most things a ME student does can easily be done on an "average" priced/performance laptop these days.
If however this is for exlusively drafting in open 3D modeling and other heavily graphic-dependent or processor-dependent applications, you'll be needing to buy (or build your own) high-end machine. They're basicly what most people these days would consider "gaming machines" because they need the high-performance, except they're not for gaming or fun, the high-performance is actually needed to take care of buisness. Good modern 3D modeling or calculation simming computers want the same things as good modern gaming computer: busty central processers (for the sheer mass of processes/calculation/formulas that need to be computed), busty and independent (from the central processor) graphic processing units/cards (for any large or detailed 3D modeling work, such as is done in Computer Aided Drafting), all the RAM they could need to adequatley handle and not choke up the busty processor when doing heavy models/calculation, a large FSB (front side BUS - which roughly translates to "lanes on the road", the more lanes you have the more cars/processes that can pass through that stretch of road in the same amount of time), adequate cooling (busty processors, GPUs, RAM, etc. needs it, but it doesn't have to be purty), multiple displays (I know, not for laptops, but my work rig has two displays and if I could I'd like to never go back to just one, one is for email or looking things up and my second one is nothing but the CAD application).
This may be a tricky rope for you to walk and you will likely want more specifics of what your son will be doing on this machine in class. Maybe he's been real good and there's a little disposable income around to buy him that 2-2.5 grand laptop, maybe he's being naughty and thinking this is a way of coning a freebie gaming laptop outa Ma and Pa. Chances are, if you're like most us mortal men, you'll be spending many hours finding an affordable and adequate machine for your son's schooling in the days to come. I've personaly had good fortune in the past with manufacturer refurbished laptops, I know others haven't, but my best hunch is that most were returned for stupid/simple things that were more user-related than computer-related.