“Nothing happens until the night before it’s due.”
Your teen isn’t ignoring Friday. Friday doesn’t exist yet. An ADHD brain keeps time in two zones, now and not-now, and a deadline sitting in not-now is a rumor it cannot feel. Thursday at nine it finally crosses into now, panic supplies the urgency that was missing all week, and the work starts at the worst possible price. The panic isn’t manipulation. It is the only start button the brain has found.
This strategy installs a cheaper button. You are not teaching them to care about Friday; you are moving Friday into now, where their brain can actually read it, before the crisis has to.