I've taken things away from him that he enjoys, but how much is too much to take away? How should I reward him and what is a good balance between rewards and discipline? I really want to work with him at solving this problem before he begins high school next year.
Do not think that your son is unconcerned about his grades. No matter what type of attitude students project, almost all truly want to succeed in school. Few, however, can turn things around academically without help.
You need to have a conference right away with all his teachers to find out exactly why he is doing so poorly in school. Once you know what is causing your son's difficulties, work together to draw up a plan to help him improve his grades.
For any plan to work, your son must be deeply involved in its creation, or he won't be willing to support it. Make sure he attends all conferences designed to help him.
Your son certainly needs to get in the homework habit before high school. Because the work is becoming more difficult, doing homework really reinforces what is being learned in the classroom and leads to success at school.
Just using rewards and/or penalties is not the best way to ensure that your son does his homework. A better way is for both of you to agree on a homework contract. These contracts have solved homework problems for many families.
A contract will establish exactly how, when, and, where homework is done and can also include rewards and penalties that you agree upon together. Click here to find a sample of the contract.