Sounds to me like he’s just plain old mentally disabled. Like, he literally has difficulty understanding events except in terms of how they’re directly about him.
In all seriousness, if Turmp had serious mental health issues to begin with – which isn’t a huge “if” – how is being President likely to affect that? I mean, if I started to think the TV was talking to me, I would at least on some level be able to see I was having a psychotic break.
But the TV is talking to Turmp. He’s in a position that’s almost entirely insulated from normal. If your grip on reality starts to fail in that situation, it’s likely to fail all the way.