Autistic teen’s fantasy world mistaken for reality

I was wondering why you're so sure these aren't delusions. Please could you elaborate?

Because they have become more elaborate as time has gone on. And I know him so well of course. 

I don't think that that necessarily means that they are not delusions. Given how distressed he is and that he is already diagnosed with depression, I would suggest that he sees his GP to discuss it further. It is possible for depression to lead to psychosis (psychotic depression).

He is ok most of the time. When he gets bored or tired he falls back into the abyss. He used to admit that the “delusions” didn’t last long. Now (since being told that means they’re pseudo) he says they’re constant. 

Have the delusions/pseudo-delusions got worse since he saw the psychiatrist? I'm not a doctor, but it sounds like he needs to see some kind of mental health professional as a matter of urgency if only because of the distress it's causing him.

Is it possible to see a different psychiatrist through CAMHS? I know it used to be difficult, unfortunately.

Have the delusions/pseudo-delusions got worse since he saw the psychiatrist? I'm not a doctor, but it sounds like he needs to see some kind of mental health professional as a matter of urgency if only because of the distress it's causing him.

Is it possible to see a different psychiatrist through CAMHS? I know it used to be difficult, unfortunately.

He is ok most of the time. When he gets bored or tired he falls back into the abyss. He used to admit that the “delusions” didn’t last long. Now (since being told that means they’re pseudo) he says they’re constant.