Is alternative medicine effective for childhood ADHD symptoms?

I am sorry to hear of the loss of your brother.  It must be very difficult for your sister-in-law to be bringing up her children on her own.  I can see you are feeling for her seven year old, who sounds as if he is larger than life and overly energetic!   

There is evidence that symptoms of childhood trauma can mimic those of ADHD, and as your nephew lost his father two years ago, and this may have impacted upon him emotionally to the extent that he is not coping with everyday life or himself. 

Assuming however that he indeed does have ADHD, here is some information that may be of help to you:

ADHD is a neurodevelopmental disorder identified by symptoms of inattentiveness, hyperactivity and impulsivity, and it is estimated to affect 3–12% of school-aged children. Conventional treatments for ADHD include stimulant medication and/or behavioural therapy, which have both been scientifically proven effective. Although widely accepted as the most compelling ‘evidence-based treatments,’ not all children respond well to these treatments, and some parents are unwilling to medicate their children, and are unable to access counselling for behaviour modification.

This then opens the door to the less conventional or alternative treatments, and studies show that a large percentage of children with ADHD are treated with one or more complementary and alternative medicine (CAM) therapies. 

These include restrictive diets such as the Feingold diet, food colouring elimination, sugar elimination, nutritional supplements, essential fatty acid supplements, mind body therapies such as exercise, yoga, meditation, neurofeedback, Cogmed (a commercially available working memory training computer program), and certain occupational therapy techniques. 

There have been many studies trialling alternative therapies but unfortunately none are held as solid evidence for the efficacy of these therapies due to methodological flaws in the studies, and so the American Academy of Paediatrics does not recommend any CAM therapies for ADHD.  This does not necessarily mean that it would be a waste of time and money to trial any of them yourself, but it would be wise to choose a treatment that has some good anecdotal evidence at least.  One of the above named treatments, essential fatty acid supplementation, was found to be modestly effective, so may be a good place to begin.