Earlier quoted context omitted.
Speaking as someone who only got our ADHD diagnosis in our late thirties and our autism spectrum diagnosis at forty fucking two, please consider just telling them. That could be years or decades of social, pharmacological, and even legal assistance that they deserve and need and aren't otherwise getting.
Also agree with this, but want to caution: Bring this up as gently as you can Don't accuse them of being ADHD, or insist too strongly If you do bring it up, I would say make sure to really emphasize that you don't think they need fixing. It's something that might help them overcome their own struggles, not something to make them a better person for others, you know?
Everything I am really good at, I am really bad at, depending on context and the wobbly compass that governs my internal motivation.
It is definitely not all bad. Without my hyperfocus, my life would be unrecognizable. I would be unrecognizable. Hyperfocus is core to so many things I am good at, care about, and have achieved.