Are you force marching him through his education? If so, maybe it's time for a re-evaluation of his learning process. Is there a way to engage him in a different fashion. I clearly realize which forum this is, but if the classical model is not working for your son, maybe you should engage him in a different method. I know from personal experience, if I enjoy something, my speed of learning and retention of knowledge is exponentially increased.
My son is very logical and has the same brain wiring as me. He and I click on a certain level when it comes to learning. I have a challenge with my daughter in the she is quite different from me. I'm going to have to (she's still in Montessori) taylor a different education environment and process to her needs. I know that if I try to force feed her the same process as I'm giving my son, WE will have problems. I don't want my children to hate and despise they're education, I want them to love the process of learning and I feel it's my responsibility to help them find the way that best fits to that goal.
And I've seen both my children (5 and 6) work independently for hours if given materials that engage them in a way that meets their needs. It's not labor to them, it's love - well, a little of both.