While there are dietary changes that can help (if the child has a very unhealthy diet). I must admit that during the almost 3 years that I have been watching/contributing to this forum, I have never seen anyone who has written back and said they have had any major changes to to natural remedies. I would think that if they made a big difference, we would have known about it. Or it could be, the remedies worked and the parents never bothered to write back. Whatever . . .
The nice thing is that most of those remedies are healthy and won't cause any harm.
Other things to think about. Due to the amount of kids these days on medication, the meds and the doctors are much better than when your brother was on meds.
From your description of your brother, it sounds like he was over medicated. If he still seems that way as an adult I am guessing that depression and meds associated with that are more to blame.
One thing to increase the odds of your child succeeding is to make sure you have an experienced doctor. A pediatric psychiatrist is probably the best way to go.
Whatever you decide to do - there is one thing that you must do - and that is to become an expert in ADHD. There is a tremendous amount that you can do to help your child, but you have to gain that knowledge. This is something that can affect him his entire life. How he learns to deal with it, cope with it, conquer it - is in your hands. Don't fail him. Good Luck ! ! !
My daughter is 7 as well and is actually on Concerta. Her teacher told me the same thing...she tries to do her work but just cant focus on it long enough to get it done. She has been on the meds for a year now. Her grades and attitude have changed completely. She does her school work, she can follow directions now (multi step directions) and she can sit still and listen. The side effects that we have noticed are sleeping and eating problems. She has never been a big eater to begin with, but she is a lot slower now than ever before. Sleeping...she goes to bed at 830 and typically doesnt fall asleep until 930ish.
We tried the diet alternative as well. No caffeine, sugar, etc but then that just didnt do enough for her. I didnt want her grades to slip or her to be held back a grade because of it.
The way I see it, paying attention and finishing homework/school work is something that can be learned. If she is on meds for a few years and her behavior becomes a habit, then it is worth it for us.
Good luck!