Upload & Sell: Off
there was another thread with someone asking about switching to mac... can't recall which forum, but i'm a pc->mac switcher and now mac lover, and i posted a lot in that thread.
i dare venture that once you try out the mac, you'll love it. the beauty of the mac system is it's so easy to use, but also so versatile. and since Mac controls their hardware as well as operating system, Apple is a one-stop service place for both hardware and (Apple) software problems (especially handy when you don't know which is the source of the problem).
don't forget, there are plenty of ways to sell the expensive pc laptop you just bought, and recover most of your cost on it. especially if it's in like-new condition. of course there's ebay, but if you're insecure about selling on ebay (i am), you might try your local craigslist, so you can meet the buyer in person. some people have sold computers on this site's buy/sell forum. there are forum sites for all kinds of pc, mac, lilnux, etc. heads just like this, with communities just as trustworthy, that you could sell to also.
i've heard of many schools not supporting either the pc or mac... in my experience, it doesn't mean that you can't use the unsupported computer, just that they won't be responsible for tech support on it. for me, that's never been a problem (my mac is not supported by my grad school), because i'm comfortable troubleshooting it myself (i used to work in IT). i also know other non-IT heads using macs in my school, and they're fine. not to be inflammatory, but i'm not sure your son would want to try the vice versa though - a windows pc in a mac school - unless he's comfortable troubleshooting it himself ... with the heightened potential for viruses, spyware, etc. on windows, he'll have some extra work to keep the machine going smooth. the CAD or whatever programs the school uses may not have identical counterparts in windows software also. if his classes in the future will involve computer classes where he learns how to use X software, he will at least have some inconveniences or outright obstacles to following along, e.g. software walk-thru tutorials in class.