Have you asked him what you think you all should do? If he was an A student before and is doing poorly now because he's bored, he has to be aware on some level that continuing like this will only lead to more boredom--he'll either fail and have to repeat a grade or he'll be put in lower level classes with even more dull work. If you can talk to him in a sit-down, heart-to-heart kind of way and lead the conversation in such a way that he admits that he's not happy with his grades and would like to do better, then you can also lead the conversation around to HIM deciding what he should do to change the situation. It may well be your idea, but you can manipulate the conversation so that it comes out as his idea. With his "ownership" of the solution, it's far more likely to be successful. Some of that might just be admitting that it IS boring and tedious to do this stuff, but sometimes you have to put up with boring and tedious to get where you want to be. He may surprise you with some ideas--perhaps some activity he'd like to do that can be his reward for getting through his homework (along the lines of if he does his homework every day of the week, then he can go to the movies with his friends on the weekend, or he can't go out to play basketball until he's finished studying--don't make it be a big expensive reward, but rather something he likes to do daily or weekly already that he only allows himself to do once he's done the stuff he has to do).

Some of what he's dealing with may just be internal disorganization, which is pretty typical of the age, and he needs to learn for himself what it takes to get himself moving in the right direction and keeping on track with his work. Again, see if he can come up with ideas for solving the problem--maybe he needs visual reminders like a dry erase calendar with all of his tasks on it, or maybe a good alarm clock to keep him on task while he does his work.

But I really think the key is to get HIM involved in the solution. I suspect that if you just add work on he'll see it as punishment and dig in his heels further.

Sarah