ADHD and changing behaivors

My 15 year old grandson has been on ADHD meds for years.  As he is getting older other symptoms are evident.  He is exhibiting anxiety, OCD behaviors.  He is on Focalin and Paxil was added and recently increased.  Now he is exhibiting some bizarre behaviors--his social interactions are poor at best, he is saying wierd things like, "someone has broke in our house and look here is a bag with my watch, underwear, and 20 questions game they planned on stealing".(It was obvious no one broke in). He is smart and will write and tell you alot about history, current events, etc. but is failing in school. He goes everyday, but doesn't turn in assignments even if he completes them. He is not exhibiting or talking about hallucinations.  I am wondering if this is a response to medication combination. He goes to a mental health center for his meds, but sees only a nurse practicioner and is lucky to get appointments once a month due to their busy schedule.  I am rambling on too much, but am afraid for him and want to help him. He seems to have regressed so much the last 6 months. Any feedback or suggestions would be appreciated.

[Sandman2]

   My first question is who prescribed the Paxil?  Hopefully, not the nurse practitioner.  Google paxil to see why.
   It does sound like the Focalin is not as effective for him as it once was.  Has the dosage been changed lately?  As boys enter their growth spurt, the dose usually is increased.  It sounds like it is time for someone other than a nurse practitioner to do a complete workup.  Tell the nurse practitioner that the meds are not working and that you need to see the doctor.  Make the appointment now, as it probably will be a while before it happens.
   Also is he on an IEP or a 504 plan so that he is not punished for handing in late assignments?