ADHD and executive function disorders are separate but overlapping diagnoses. In our experience a neuropsych. evaluation can diagnose executive functioning issues, but not ADHD. ADHD is diagnosed by a psychiatrist or even primary care using a questionnaire for the teen and family.
The problem I have seen with one parent resistant to this kind of thing is the blaming that happens. There is a book entitled “The Myth of Laziness,” a title I really like.
Anyway…..Camp is supervised but away from home. Job or volunteering can help a kid feel mature. There seem to be lots of options. Pre-college programs that are academic could add stress or add motivation- hard to tell!
Movement and meditative practices can help. Tai chi is martial in origins and young men seem to like it. Just a thought.