Unsolved Behaviorial Mystery, ADHD, food allergy,

I am concerned about a young friend of mine. He is 5 1/2 years old. He has been diagnosed with ADHD, and has been since he was three. He is an extremely intelligent and bright individual when you can get through to him. However, he is a terror on bad days. He has been taken to multiple specialists in the area. He is currently being medicated for his adhd but the medicine can create as many problems as it does solutions. He is a sweet and almost normal little boy when medicated properly, but it only lasts for an hour or two at a time. Shortly after medication he is depressed and lethargic. There is a short period where it is okay, but before the next dose is due he will have become aggressive impulsive and nearly unresponsive, wet and/or soiled his pants, started histerically running jumping and screaming. The ups and downs are unbearable, but the doctor reassures it will better when we find the right kind of medication.

In addition to the symptoms of ADHD he has had other health problems throughout his life. He is allergic to milk, garlic, blue food coloring, and a few other foods. We keep these out of his diet most of the time. He had a hearing problem but the tubes in his ears seem to have helped. He had asthma but this seemed to be alleviated when the food allergies were identified.

There are a few major red flags that lead me to suspect an underlying problem that hasn't been diagnosed yet, these symptoms persist regardless of medication. He drools excessively, and has his whole life. He still wets and soils his pants, he isn't slightly motivated to be potty trained. He refuses any food or drink 90% of the time, unless he is exceptionally hungry, and he often becomes hysterical before he accepts anything to eat or drink. He also doesn't get enough sleep, he refuses to nap or go to bed without careful coaxing and trickery on his parents part.

His parents are both very intelligent people. He has a dedicated mother who does everything in her power to help him. She has mild ADD but is successfully medicated. She works full time and has three other children to care for and a husband that often makes things worse rather than better. We suspect the father has either Aspergers or Narcissistic Personality Disorder, but he refuses to see a doctor.

I know this is a lot of information, it is a complicated case. I am very concerned about the well-being of this little guy. I feel he is a wonderful individual , but his personality is masked by health and behavioral problems.

Does anyone recognize any of these symptoms as part of an untreated issue?

Thank you for helping!