Define "average school." If you're talking about anything below t14 ITE, that's when you need to be worried about getting "overlooked in the job market" entirely.
I mean, fair enough. But if he really only wants shitlaw, most of T1 should be okay.
Edited to add: Again, you have to reallllly want to be a lawyer to justify resigning yourself to huge debt and a crappy salary. If that doesn't sound like a good time, then yes, you shouldn't go to a school outside of the top 10 or so.
Whoa...slow your roll! First, we need to define "elite" versus "top". Top-10 schools are not "top" schools...they are "elites", as are the next 8-10 schools. HYS are the "most elite" and CCN (as well as PMNVB) are power schools that are right behind them. But the rest of the top-20 or so are still "elite" schools. "Top schools" are anything numbered or perceived in terms of "lay prestige" to be 21-50 or so, and there's not a lot of difference between them, except to the extent that some wide-eyed 0L puts stock in the USNWR rankings. Law school definitely has some elitism going on, but it's not as exclusive as you make it out to be.
Grads from UCLA, Texas, USC, Vandy, and WUSTL do just fine. And grads from Minnesota, Boston College, GWU, Illinois, Wisconsin, Ohio State, Wake, Emory, UNC, Tulane, W & L, and W & M do great also. Yes, the economy is tough, and it affects the grads from lower ranked schools moreso than those from the elites, but if you make the top-50 and even a few schools outside of it, you have done pretty well for yourself. The top-50 is like the difference between getting a Bentley or Ferrari (HYSCCN), a Mercedes-500 or BMW 7 series (#7-20), or small Mercedes or 3 or 5 Series BMW (#21-50). People should still be pretty excited about that small Mercedes or smaller BMW...it's better than a Honda/top-100 (which is still "decent"), and certainly better than a Hyundai (T3), and let's not talk about some used Pinto or Pacer (T4).
The difference between an elite school and a top school is that you can finish just about anywhere in the class at an elite school (but near the bottom) and still have a chance at a good paying job. At least, that's the way it is in a decent economy. The difference between the top schools (21-50) and the rest is that you can get a good job by finishing in the top-half of your class. You may have to use career services more, but if you can make top-50% at a school ranked 50 or above, you can get a good job, BigLaw or not. At top schools, you will generally need to be in the top 10-20% to go BigLaw. At the rest of the schools, you're talking top-5-10%. At a T3 or T4 not named Howard, Suffolk and a few others, you need to be the king/queen bee...top five or 10 "students"!
And remember this, employers don't think in terms of ranking, they think in terms of familiarity with the graduates of particular schools. If a firm in L.A. has a really good history with Loyola grads, Minnesota grads (despite hailing from a consensus top-20 school) are at a disadvantage, if the hiring partners don't know Minnesota or its grads very well. They might hear or understand that it's a great school, but they don't know if a Minnesota grad can do entertainment law the way a Loyola grad can, and they may not have anyone in the firm (in a key position) with loyalties to UM. It's politics, and grads from every school but HYS can bank on experiencing it to some degree or another.
That is the type of dynamic that plays out when career services gets involved. If it's OCI, obviously the firm is coveting graduates of a school because they are simply top grads from certain schools, or, because of their familiarity. But once we are talking students ranked in the 60th percentile, firms are going mostly on familiarity.