A blood panel may point to Polycythemia (too many red blood cells) as well. My son has this. It presents a lot like ADD. It's simple to treat. They syphon off about a coke can's worth of blood every 6 weeks.

Your aon sounds like my 21 year old. He has ADD and it causes him to be very forgetful, unorganized and has trouble keeping up with the rest if the world. As gearhead says, he should have a blood panel done. Thyroid, anemia and B12 deficiency come to mind as possible causes of 'brain fog'

Has he had a complete work up at the doctors office ? A low functioning thyroid can cause memory problems in some people. It can be easily diagnose with a blood test and tends to run in families. It's just a thought . My daughter has the same issues as well and some of her meds make it worse .