As a person who has taught parenting classes (I am also a certified teacher...and I have sensory integration dysfunction) for years, I can tell you that there are a few different ways to go.
I will tell you that the diagnosis of ADHD has skyrockted and so had the use of drugs for it over the last decade or so. In this case, the Dad has it, so, the kids could very well have it, too.
Sometimes a gluten free diet does work for SOME children when it comes to their behavior...Especially if a child has sensitivity to gluten !! Many kids w/ ADHD have overlapping allergies !
In some cases, it does not make much of a difference.
I once met a woman who took her kids off almost all artificial dyes, colors, and sugary foods. Her kids behaved sooo much better.
To follow a doctors plan: Feingold.org
Doctor Feingold was a pediatrician and an allergist. His diet eliminates dyes, colors, aspartame, etc... It's really worth giving this a try !!! It has worked for so many WITH ADHD.
Some parents choose to give their children w/ ADHD a very high quality fish oil.
There is more information on CHADD.com. This is a great website for those who need information on ADHD.
Then, there are other parents who have tried all of the above and have found that their last resort was meds.
I would try the suggestions above and resort to meds only if absolutely necessary.
Also, she can call around and find an Occupational therapist that works w/ children with ADHD. I have to do OT for my sensory and it keeps me in sync and it is calming ! Some Moms have brought their kids w/ ADHD to OT and love it !
Tell her to take out a few books at the local library. If her kids are girls, the best book is by Kathleen Nadeau, PhD. Although, I just reread the post. She has boys...so, ask the librarian for rec books on ADHD.
She should take them to an allergist and have them tested for food allergies. Over the yrs, kids who have been thought to have ADHD might have an allergies to gluten and/ or milk casein.
ADHD can overlap w/ allergies, sensory, depression, anxiety, etc.
The kids would have to be tested by an allergist --and, then, neuropsychologist to be sure.
Or, she could take the kids to a naturopath doctor who works w/ individuals w/ ADHD.
Years ago, there was research that SOME kids were being labeled ADHD when the kids were actually very sleep deprived.