A third option is that he does have ADHD and you, a bystander, are doing the misdiagnosis.
IMO for disorders like this it’s almost better to view it through the lens of the available treatments. Is the treatment, on net and relative to other possible strategies, going to be a positive impact on this person? If yes, then whether they have apparent Disorder X (a figment of imagination) versus actual Disorder X (which is itself also a figment of our collective imagination) isn’t super relevant. Obviously in the case of ADHD the prescription drugs are pretty intense and have pretty severe negative consequences, so this framework in that case would probably even yield that people with actual ADHD but mild forms shouldn’t have those drugs pushed on them either.
IMO for disorders like this it’s almost better to view it through the lens of the available treatments. Is the treatment, on net and relative to other possible strategies, going to be a positive impact on this person? If yes, then whether they have apparent Disorder X (a figment of imagination) versus actual Disorder X (which is itself also a figment of our collective imagination) isn’t super relevant. Obviously in the case of ADHD the prescription drugs are pretty intense and have pretty severe negative consequences, so this framework in that case would probably even yield that people with actual ADHD but mild forms shouldn’t have those drugs pushed on them either.