Okay. It sounds like buy in is a big component. I can't think of what would motivate DS, other than screens. So maybe I could tell him he will earn screen time by filling in his planner effectively and turning in assignments?
I would be very, very careful if this is his main form of entertainment/unwinding. You don't want to end up in a situation where he doesn't earn, gets angry at himself, and spirals downward instead of upward. (Ask me how I know this.... )
Does your DS generally respond to rewards? Some kids do, some don't.
DS13 does, but ultimately what was powerful for him with schoolwork was success. We said, "We are going to help you do this right so you can see how well you can succeed." Then we did everything we could (including putting help into place at school and making clear to DS what that was for) to help him get things done.
Eventually (and it did take a while) he did finally see that when he gets the planner checked, he IS less frustrated and DOES do the work better and DOES get better grades. This learning is not fast.
I can't bring myself to completely take away his computer time, punitively. He has multiple projects that are actually enrichment for him (video editing, an online "build your own country" simulation), and he also seems to really need music for his emotional regulation.
Then I wouldn't touch this.
Things to try:
--Homework to turn in goes in a clear folder so he can see it in there.
--Homework to turn in gets brightly colored tape flags
--As each item is handed in, it gets crossed off in the planner. At day's end, anything not crossed off needs to be found and turned in.
Ultimately, there is a limit on what you can do from home. (This is all I've got.) What helped DS was regular support at school plus the accommodation of emailing work.
