"I didn't like the idea of getting one but they begged for so long we finally gave in."
Does he think if he puts a stand long enough or beg long enough he will get what he wants no matter how you feel about it?
"healthy food that they offen complain about. "
Is he drinking alot of caffiene?
Keep in mind with alot Adhd kids it does the opposite for them than those who are not. caffiene will make them tired. Are you giving him suplements most people take for an energized feeling well that right there could make him tired.
Some of those protien powders contain steroids even though they are legal and small doses someone with little weight could cause there body to go loopy.
There are so many factors here you will have to find out which one is the most important and work on it.
Like getting dressed in the morning... he is getting dressed? if yes FANTASTIC! Is it nice? Compliment

The great things about kids is they will not starve themselves to death. if he is not eating at the table make sure all junk food is out of the home. he is eating somewhere.
Though I would make a appointment with the doc. Do not tell him just take him. Maybe he will feel comfortable telling the doc with what is going on and if its nothing then the doc can take tests to see if its more dire.
Dont let him beg you out of it. Stay firm

you can do it
