prior to industrialization. Poor kid and those like him are meant to be in a forest hunting for his tribe or village... Or out in a field plowing to produce food for his family. Instead, he's being asked to sit in an uncomfortable chair among 30-40 kids and be taught for what 6 hrs, 5 days a week, 180 days a year.
I feel for those boys. ADHD, ADD etc... all "illness's" that seem to magically appear in the last 25 years.
Be patient, love him and guide him to channel his energy into things he's passionate in. His age is a time of his life where he learns who he can trust and depend on in life. People outside his family will natural have little patience for him, that's where you guys come in. Don't worry about what others think, he's your son. They can worry about their own problems, they may not be ADHD but they have problems too.