I'm presuming that your son is using the excuse that he doesn't like his teachers to avoid completing his work. I'm also sure that you have told him that it doesn't matter whether he likes his teachers or not. What will be, and what has been, the consequences for not doing his work? Have there been conferences with the teachers and the school counselor? Has your son been present at those conferences? If not, make him go every time.

Family and school need to work as a team. What is the plan to check on him? What are the consequences for completing or not completing his work? Will he get to go on vacation with you or will he be in summer school? Get creative! Give him a choice: This is what will happen if you choose to do all your work. This will be the result if you choose not to do your work. Emphasize the choice and his responsibility. Then do the hardest thing in the world for a parent: Let him choose.

This is basically your son's problem, but you as parents can set the boundaries for him. Encourage him to succeed, then follow through on the consequences you have set.