If you think you have a serious concern, you should see a doctor. I know a lot of people have a distrust of them, but if your son has ADHD, the single most proven solution is drug therapy. There are various counselling and diet options as well, but you have to watch out for quackery (despite your reservations, the amount of erroneous, biased and dangerous info in the general public is much higher than that amongst medical professionals).

But a first step might be an ADHD patient organisation who might advise you.