I have an adhd/odd 17 year old too going into his senior year. Very similar situation where he was failing some classes because he just didn’t do homework and it’s ext rare that he’ll study for exams. What worked for us, and it was just in the last quarter of his junior year, was his love of computers and gaming. I told him if he failed a class or got any zeros on homework he would lose his computer until summer break. The difference in him was night and day. That last quarter of the school year I no longer had to check each teacher’s website for homework, and no longer had I had to have him show me he completed it. He knew the consequences. I had teachers emailing me saying how much more he was engaged in class and that he was completing work on time. He got his grades up and passed his classes, finals, and Regents exams. It’s the first time I let him truly fly solo. Every week I’d check parent portal to make sure he was on track. Does your son have something that he’d hate to lose that you could use? Other than that truly the best solution is to let him fail. I know as parents it’s extremely hard to watch our kids fail but they do learn better that way. He has to learn that if he doesn’t perform in life he won’t get anywhere. Does he work? My son has a part time job and hates it, which is good as it makes him see that if he doesnt graduate then that job could be his life. Our sons seem very similar.