I am a male, now 79 years old. I could not read in third grade. I was diagnosed at age 65 with ADHD, Dyslexia, and Dysgraphia. I am an Eagle Scout. I hold degrees in physics and mathematics with a minor in chemistry and I am a Registered Professional Engineer. My children are ADHD and my grandchildren are ADHD and they are also bright. The public-school system is just barley learning how to teach children with ADHD.
If your son is doing grade level work you are lucky. The socialization of a human-being within a culture is a never-ending work in progress, as both the person and the culture change. He will learn how to cope socially over time as all ADHD individuals have to do. Because of our physiology, most ADHD individuals are socially immature through their late teens, and some into their early twenties.
In my experience, the only reason to hold a child back is if they are not performing academically. My parents knew I was bright and even though I was not performing at grade level they did not hold me back. By the seventh grade I was reading at an eleventh-grade level and performing academically at a “B-” level, even with all of my undiagnosed ADHD related issues.
Support your son with focused specific affirmations as to his qualities, abilities, intelligence, and goodness. With your backing and full unwavering support, he will do the rest.