Sometimes tough love is the best love. You just have to do whatever it takes sometimes. ADHD doesn't make a kid a bad one, but it can make them a lot more difficult to deal with. I know a lady in San Francisco who works with ADD and ADHD kids and their families.
My brother was/is ADHD. Back then they just assumed that someone with it was just a "bad child", now they diagnose it as a condition.
I'm not even going to pretend I know a thing about parenting, but shouldn't you at least still show him that you love him? I mean, don't cook for him, don't do him any favors, all that jazz, but don't make him think that you're on the brink of disowning him. I think that'd just make him lash out more in the end. But again, like I said, I'm not even gonna pretend I know what I'm talking about (just throwing it out there).