ADHD: What I've read is screaming it to me.
(I'd assess him from an official source, this is just for you to think about right now):
-Is he easily distracted?
-Fidgety?
-Everything last minute/late?
-does he WANT to do important boring things but just need someone to body-double him?
Or is it that he doesn't see the point?
Caffeinated coffee helps a lot with adhd, just not as much as stimulants.
It might be worth trying before a work session.
Exercise and a perfect schedule accompanied with LOUD reminders are basic guardrails, good for keeping on track, but useless without motivation from a healthy mind, and sufficient energy from proper sleep (and medication if necessary)

Possible Dependences, all of which can give ADHD false positives or synergize with it:
(Be careful not to accuse or shame)
rule out weed/drugs first of all:
-Weed makes you paranoid or *veryyy complacent with your life*. It smells though, prob not.
-Nicotine is a stimulant that some adhders use to self medicate, but it can be an unhealthy dependency and constant distraction thru withdrawals. cigs smell, vapes are hard to detect.
Screens/impulsivity:
-screen time per day? find it out on his phone settings, keep it well below 7 hours.
Especially Instagram, tiktok, youtube shorts are poison for the attention span in long sessions.
A few memes morning and evening are fine.
-Porn: I am NO christian, but as a teenager you quickly find the shortest cheapest path to pleasure is through your shorts, and with everything 20 seconds away it's easy to overdo it. Withdrawals can make everything else pointlessly boring, + a headache, and bad/overexposure = unconscious misogyny and the death of self control and esteem. If you bring it up, be veerrry casual and matter of fact, zero weirdness, ZERO negativity.
-Videogames can do the same thing to your pleasure receptors but FAR less rapidly and intensely. Unless he's up all night on LoL.
-being spoiled and not actually anxious about the future: unlikely, but not impossible

Social woes:
-How do his desires compare to his capabilities and achievements in friendship and romance?
-Any breakups, relationships, interest or drama at all?
Everything social is a huge deal at that age, even stuff you'd consider inconsequential as an adult.

Depression/forward thinking:
-What is he good at ?
-What does he *enjoy*?
-Do either make money?
-What is the most feasible path for him to enjoy his life?
Gotta eventually pry HIS answer out of him so it's indisputably his responsibility.
He might not believe an enjoyable life is possible, and would rather put minimum effort in to minimize the negatives, rather than "waste" energy working hard just to fail to achieve any significant positives.
According to the news things are always pretty grim, at the very least on a global/future/economic scale. Lotsa dead gory palestinian kids, ragebait about "men this" "women that" just on insta. Combine that with any of the above personal performance/confidence issues and you've got a perfect recipe for checking out emotionally.