No. Patrick isn't advertising or otherwise representing himself as a medical doctor. There is no law against a layman--
qua layman--offering an unqualified medical opinion. If you tell me that you have a headache and I tell you it's probably from eyestrain, I am not "practising (
sic) medicine without a license."
It isn't defamatory for similar reasons. Patrick is merely offering an opinion. If he were a mental health professional, he could be seen to be making an improper diagnosis or behaving unprofessionally, which could be defamatory.
Not if we consider the totality of the evidence that we have access to at this point. There is good evidence that Patrick SWATed himself, marked his property with an erasable marker, and pretended to be harassed. He doesn't exhibit any persecutory delusions--he is trying to appear persecuted.
There is nothing in Patrick's behavior to indicate that he has delusional disorder of the persecutory subtype.
He
may have
NPD or just be arrogant. Either of those and his IQ of ~85 would be adequate to explain all of his behavior.