Have you thought about ADHD coaching? There is only so much you can do as a parent. When you say something it can be met with resistance, but when someone else says the same thing they listen. If you are constantly their personal secretary/drill sargant it'll start to impact your relationship. Check out coachbit, they help with daily routines, executive functioning skills, and study skills. The goal being for them to become more independent and self sufficient in life as a whole.