Wondermom, as a teacher and tutor to many kids, I have certainly come across kids that fit your son to a T. I understand your frustration and his. I can only say that, when your son gets to college, there are plenty of teachers that have homework as an extra credit, or as a grade-turner, if the person is on a cusp. But this is not the case with all teachers, some count homework as a small percentage, others as a larger percentage.
I tell my students, it's a game, and it's rigged, and its your choice (per class) as to what you want to be your outcome.
Perhaps if your son looked at it this way, he'd be more hopeful. But now, as it stands, the game is stacked firmly against him that he has to turn in assignments. Tell him it's a math challenge; perhaps he only needs 60 percent or so (in that he can toss them off in a few minutes) just to get the points? PLAY THE GAME, I tell my students. And do it quickly, because I know you hate it, but please play. TURN IN ASSIGNMENTS. Do them in five minutes. Do anything!
I can probably guarantee they won't be the worst assignments turned in...
In that way I can get some of my kids through the courses they are bored to death with. BTW my work primarily deals with CC kids, and LD kids, etc.
In regards to Davidson, they have homework there too... so it's wise to just learn to do the work, period. (and if it is truly below one's station, then one must quickly churn it out as fast as possible.)