I have a few questions to try to sort things out.
1. Who diagnosed him and who is giving him that dosage?
2. Has he seen a neuropsychologist, a Developmental Pediatrician, or had a multidisciplinary evaluation done at a children or university hospital? Something seems wrong here.
3. What symptoms does he have off the medications?
4. Any psychiatric or neurological stuff in your family on either side of the family tree? Mood disorders? Substance abuse/alsoholism? Symptoms of possible high functioning autism? Jail?
5. Has he tried any medications besides stimulants and, if so, did he take them while NOT on stimulants? Ever tried a mood stabilizer or an antipsychotic (Risperdal, Zyprexa, Geodon, Seroquel, Abilify). Sometimes the effects of these medications are knocked out when stimulants are also taken.
6. Any speech delays, inappropriate/clueless social skills, rocking, repetitive movements, obsessing, lining up toys, poor eye contact with strangers, weird vocalizations?