@getlostinthewild Sending hugs, that is stressful.
Where specifically are his struggles? Does he not do his work or he does it and it's wrong? Is he bored or so far behind he feels it's pointless ?
What is the school system like there? Are there other types of schools with different educational approaches? For example, here we have normal schools, magnet schools (normal but extra funded so specialize in something), charters (more leniency with curriculum and educational approach) and private.
When we got custody of my teen, he was 10 and hated school. He is pretty severe adhd and had always had a negative experience. Constantly in trouble. He was so far behind in everything that his first state test with us he scored at a kindergarten level in reading and math. We would read to our younger kids each night and he'd actually leave the room rather than sit and listen. He had absolutely no self-confidence with school and would get defensive and argumentative about everything to deflect from his own inabilities.
I put him in a school that was very hands-on learning, project-based. Building shelves to learn about math. Guerilla theatre where in order to play the roles he was excited about, he had to think about reading concepts like tone. I told him to pick any books to read, preschool or whatever I didnt care. Just read. His science class did a lot of cooking, Incorporating social studies with recipes. His school had him walk/run around the fields if he was restless. His school counselor worked on focusing skills, his teachers and I worked on blocking out assignments and color-coding where to focus. This super hands-on was something he loved and wanted to do. He wound up being grade level within 2 years and a bit ahead after. He's a passionate reader now and loves books.
So for us... it boiled down to a school type. He needed to really engage, interact, move his body. It completely transformed his school experience which transformed his attitude about it.
But that type of school isn't always accessible and it may not even be the issue at all. But I just wanted to share our experience in case any of it is helpful. That your child has failed multiple times must heavily weigh in on his own perspective of school and himself as a learner. And that's hard on you too. And it's so hard when that kind of stress just dominates your home. I'm sorry