you remain responsible for your behaviour - both legally and in terms of school performance, and parenting
ADHD may make some things harder but it doesn't take away responsibility. Get a speeding ticket, and you're still going to have to pay. Not bother to hand in assignments and a letter from your doctor isn't going to keep you from failing or being expelled. Universities may give you extra time to write an exam, but not to complete assignments.
It is your responsibility to work around your limitations. Revenue Canada is not going to be sympathetic. The courts aren't going to ignore you getting distracted while driving and then hurting someone.
Thing is, You may get distracted, and bored, and be prone to procrastination, but we know from the military and very strict private schools and involved parents, that you can do the work, you can be responsible a trouvé.