Husband refuses to accept he has ADD.

My husband of 17 years was diagnosed with ADD (7 years old). He was on Ritalin, but it gave him side effects. He doesn't function well on 9 to 5 hours jobs. He was let go more than once because of his lack of focus. He chose to be a self employed, because he likes it. He prefers to sleep late in the morning. He said he is able to focus on afternoons and evenings. I read the article that it may be related to dopamine? He likes to pace around the house everyday talking to himself. He overthinks all the time. He is prone to irritability. For example, if he accidentally drops his cup and it spills on the floor, he screams the obscene word, and just takes himself too seriously that he dropped it. It is so over the top.

He was a terrible high school student yet he received straight As plus AP classes. I read all of his old report cards. Most of his teachers complained a few things that he did NOT pay attention and took naps all the time. He does math in his head that he doesn't need calculator. His IQ is 142. How do you know so much stuff yet you don't pay attention? That you were able to get straight A grades? He has BS and MS in electrical engineering. He doesn't like to listen to their professors. He just prefers to read and do his own way. His own way. He is not a team player. His social skills are not bad. The problem is he doesn't offer information to carry any conversation. It is kinda he is turned off and goes back to his phone. His family members, friends and I often wait for him to offer information, but no.

I hoped coffee was supposed to help him focus. He tried dark coffee for the first time in his entire life and he became so tired that he slept in the bed. He also tried green tea, but it gave him headache.

Is there any tip else that may help him focus without side effects and tiredness? He doesn't want to be on a prescription again. He keeps denying he has ADD because he claims his psychologists are wrong. He refuses to seek for tips from people with ADD. He is very stubborn.