Like most children with ADHD, there may be a combination of educational/medical events going on at the same time.  Certainly outside of the US, schools can set standards of admission.  I would suggest a pediatric developmental evaluation to assess what his learning potential is.  If this is not possible, I would seek what government assistance for children may be available through youth and children's services.  Autism spectrum disorders and other forms of behavior often manifest with this triad of issues.  If you are not sure where to go, try your school and ask what is available to them.

Wayne Yankus, MD, FAAP
expert panelist: pediatrics