I am taking sevral herbs althogh some might be suspicious about it. I heard large dose of fish oil can help, just started. But I would recomend Brahmi (Bacopa Monnieri) for mental problems, it is unexpnsive and widely used in Ayurveda for mental problems and improving memory. Many years ago my EEG became normal for first time in my life after taking it... previously I was diagonesd with epilepsy, although never had an epileptic fit, doctors ar sometimes amazing. There is also one other product, Divya Medha Vati, just google it.... first it helped me a lot, I mean Brahmi,but I had another small concussion which added to previous, anyway, these herb, from my experinece, and what I heard, can make big difference.

Try to contact good homeopath. Try aslo acupuncture.... Important is avoid further injuries... and try to find natural way to treat his mental problems.... with minimum allopatic medicines.

Goods luck to you and your son.