Educationally we have hit a wall. Is it meds or is it just Aspergers? Is there anything we can do?

My son is 17 and sitting A level equivalents here in NZ.  He has strong ADHD, Aspergers and since starting on Concerta, epilepsy.  Meds are concerta, some rubifen and epilim.

Last year for o levels, we had a largely willing kid who though exasperating at times, got on, was fairly focused before exams and passed with an overall merit.  This year for A level as we do it in one year, it was a big jump up.  Things were harder and some fails slipped through by mid year, there were as many fails as passes although excellence across the board in digital technology of course.  We are currently sitting exams but I think he will fail almost all of them.  IQ Test said to be around 70%.but not on meds when this was taken at age 8.

So in detail, what is happening is this...  assignment work involves lots of research and he can sit and research for a day or two and come up with almost nothing or something that is way off base.  We have to find the websites, define the areas to look at (provide a framework) and then review and challenge all the way along.  My son cant work in class so we have been putting in 75 - 150 hours/assignment.  So yes he and I are both exhausted.  For the large six months he has been hugely distracted and has switched off completely in chemistry and maths as 'he was never going to learn anything from these people' and apparently read kindle every session.

For exams over the last term we have done some revision and quite a lot in the 10 days before exams but here is what is happening.  The info is going in but not coming back out.  There is like a complete disconnect. For example, he is doing Wilfred owen war poems so I summarised some themes that are still relevant in todays society as this often comes up and is one of the easier questions.  He read it and came in and said, its all very interesting but I don't see what it has to do with English?  Similarly I have got him a maths tutor who said, he should be able to get a pass on the exam but he had no idea whether he would.  He said he has taken on board the processes and knowledge needed but he doesn't seem to be able to access that knowledge without being prodded or reminded,

So what I have seen also this year is:  Pretty aggressive behaviour on the weekends and a kind of weird aggressive, stirring from first thing in the morning.  He even looks kind of weird and doesn't stop until there's absolute chaos.  Literallly, he can lie on the couch for 2 -3 hours watching TV and if you say anything at all, like you need to get on with some study and it starts.  Massive rudeness, aggression,really offensive name calling (not your tame 4 letter words) - these things are kind of sick.  The behaviour comes out the blue and is there one day and not the next.

School his behaviour is good, its catholic and they have detailed weekly notes.  His behaviour has been distracted most of the year.  Organisation is worse than ever, cant get out of bed, wash his face, get dressed or clean his teeth without someone forcing him to.  His Dad now takes him to school because I couldn't stand it any longer and he is late to work nearly every day.  He almost always leaves the house without shoes and socks on, coats, no personal hygiene, showers about once every ten days and only after nagging.  Has no friends, doesn't seem to bother him,  has a cat he was close to, it is dying but he now says he cant feel anything, knows its sad but doesn't feel it.

Support for disability in this country is probably one of the worst in the developed world.  Apart from seeing a paediatrician for his meds and the hospital for his diagnosis.  I have never received any support or guidance.  We have not had a day off from him for about ten years and only know anything about his condition through reading and online.

So what do I do?  I don't know whether this is normal.  The schools here don't have special services for disabled kids but they think it is normal for kids like him.  I don't know whether to take him to a psychiatrist for a complete review of his meds or a new diagnosis or what to do.  He has recently had his concerta upped but it has made very little difference.

We were hoping to get him through his final year and off to university and into an applied software/it degree but at this rate he wont make the standard to get in.  He does not qualify for a supported living allowance or help with education as he is theoretically capable of working for 15 hours a week.

Any thoughts on what to do?  Whether this is him reaching the level of functioning for him?  Whether new or different meds will help?  Whether he may need a new diagnosis?  What's up with this weird behaviour?  Otherwise he is a home loving, hard working and very responsible kid with a good sense of humour.  

I don't want to keep pushing him if he is doing the best he can but I cant help noticing the vast difference between his focus and on to it ness this time last year and today,  He has an exam this afternoon and is wandering around playing with the cat and I have to keep reminding him, there's an exam in 2 hours and its like he has forgotten.

Really grateful for any help or suggestions