I would highly recommend people interested in learning more about ADHD itself to read Delivered from Distraction: http://www.amazon.com/Delivered-Distraction-Getting-Attentio...

It's a fantastic book that explains the condition extremely well and has tons of useful information on not only how to cope with the condition, but for how family members and relatives of somebody with ADHD to best support them.

I'm basing it solely on the amounts of caffeine he was taking. If he feels he needs that much caffeine to be productive it is a very large hint.

If you are concerned I suggest the book "Delivered from distraction." http://www.amazon.com/Delivered-Distraction-Getting-Attentio...

Two suggestions I've found helpful:

You Mean I'm Not Lazy, Stupid or Crazy?! http://www.amazon.com/You-Mean-Lazy-Stupid-Crazy/dp/07432644...

Delivered From Distraction http://www.amazon.com/Delivered-Distraction-Getting-Attentio...