Wow, from the length of your post, I can tell that you are not only worried, but you must care for this kid a bit. Not sure you would have taken the time otherwise.
I am the community leader over on the ADHD forum and was asked by another member to check out your post - and I can see why.
If some of the stuff I say makes sense you may want to continue the discussion at http://www.medhelp.org/forums/ADD---ADHD/show/175 -
or here as I will watch this list.
I have dealt with ADHD kids in a school setting for a long time (check my profile) and some of them have been highly intelligent so I do have a few ideas that may be helpful.
But let me add before I go on that "sleep problems in schoolchildren with ADHD are extremely common and strongly associated with poorer quality of life, daily functioning and school attendance. http://www.sciencedaily.com/releases/2008/04/080407160751.htm and if these sleep problems can be treated, it will make a difference!
Man, there is so much to cover. All most all of what you have described, I have seen in kids with ADHD. It doesn't mean he has it, but it really makes me suspicious. Typically hyper boys get noticed early in elementary school, but if you are intelligent - its easy to get overlooked.
Lets start with ADHD symptoms. Here is a very straight forward list of symptoms - http://www.azcourts.gov/casa/Training/TrainingCourses/ADHDpg3.aspx
Now here is a more involved list that looks specifically at teenagers. I think that some of the behavioral and friendship parts will seem familiar.
This site deals specifically with gifted kids with ADHD and talks about the difficulties that being gifted creates. http://www.ncpamd.com/Gifted_ADD.htm
The final site is from an Adult ADD site. It deals with high IQ and ADHD. Scroll down to the post by Wilsonstark and read that - although the whole thing is interesting. Besides the similarities in behavior (I think) - this post also shows what the future could be like. It is something that you might want to wind up showing to his parents. The link is: http://totallyadd.com/adhdandhighiq/
Of course, non of this proves he has ADHD. But if he does, it not only would explain his actions - but it would also mean he can be helped.
I've got a feeling that we will be continuing this discussion. Read the links if they seem to fit (or if they don't) - then we need to talk about what comes next. And with the end of the school year approaching - not a lot of time left.
Best wishes - and thanks for caring enough to post!