My nephew is ADHD and my parents have a hard time understanding him.

Your nephew and his parents are lucky to have you in their corner.

I'm not sure if certain people can ever be convinced that behavior associated w/ADHD is not purposeful. I am wondering if the real question is how to help the situation so that interactions are less stressful and negative.

That said, are their situations and supports that allow your nephew to function better? For instance - short, structured interactions with minimal distractions/sensory overload? Are there signals that parents can use to help your nephew realize when he is exhibiting negative behavior and ways that he can step away and pull himself together?

Can you talk to the grandparents and help coach them on how they can contribute to a more successful interaction?

In the meantime, I love the book "Driven to Distraction". I'm not sure if your parents would read it, but it's worth a try.

How old is your nephew? My son also has ADHD, and it took quite a few years before the "extended family" realized that we weren't "raising our son without limits" or "promoting misbehavior" but that ADHD is a medical condition related to an imbalance in chemical neurotransmitters in the brain, and that's why his behavior also fluctuated from day to day. It always puzzled my mother-in-law how our son "could sit still watching TV" but not sit still in a restaurant or to do schoolwork.

In all honesty, I'm not sure that some people will ever be convinced that ADHD is "real" since there's no simple blood test to proove it yet. An analogy that might help older people to understand is a reference to diabetes. Some people may have a genetic predisposition to developing it. You can't tell from looking at someone who "has it" and who doesn't, but they might show some behaviors that are common with the disease. You might notice someone drinking more water and going to the bathroom frequently, even if it seems rude (to get up in the middle of a church service, for example.) They can't control when it happens. Some people benefit from medication to control their symptoms. While nobody "wishes" to have it, you do the best you can to deal with it, but ignoring it won't make it disappear.

I don't know if they're willing to read information from "professionals" about it, but you might look at sites like www.help4adhd.org and see if there's data that you can print out to share with them. And thank you for being such a concerned aunt.