Delusional Disorder, exacerbated by cannabis?

Short bio: individual in question has not been diagnosed with any psychiatric condition, but a GP told her she sounded stressed an prescribed xanax and citalopram. Individual has recently undergone several high-stress situations.

Someone very close to me is showing textbook symptoms of persecutory DD. Here's the thing: she initially began showing signs while under the influence of cannabis, telling me a story of how all the workers at her new job had plotted to out some of her very personal details in a public meeting, and that her remembering this event (which happened some weeks ago) had been triggered by an object she discovered that she had in her possession, and that this person of authority at her job had psychologically manipulated her into some sort of amnesia that prevented her from realizing at the time of the event that she was even being outed... I tried reasoning with her for hours to convince her that none of the details/events she was describing to me made any logical sense, and that I think she was suffering from delusions, possibly brought on my cannabis (she has been a regular user for several years, and I have never seen these symptoms until now).

Anyway, fast forward a couple months, and she still keeps "remembering" all these details surrounding this event, with this person of authority that 'outed' her initially, describing more and more personal details about her life, her associates, activities, etc. She says that it feels like deja vu, where an event that happens in current day suddenly triggers a memory of this authority figure telling her that "certain-such event will happen in your life, and then you'll know that we know everything about you, because we predicted this event would happen to you". Logically, these situations all sound like self-fulfilling delusions... She actually confronted several people that she had separate-but-similar delusional scenarios with (somehow related to the original situation), and they have both denied having any memory of the events she describes, but she has simply started believing that those people are probably lying to her because this original authority figure that 'staged the whole thing' had told them to deny any involvement or memory of said event...

For the record, I have nothing against recreational substances of any sort. I don't want her to quit cannabis because I think it's 'bad, mmkay', I am truly concerned that it is exacerbating her condition... Do I have anything to stand on with this belief? Will cessation of cannabis help her, or have no effect?

I have encouraged her to seek professional help, but she is not even fully accepting that these things she is experiencing are not real, and so doesn't really believe she needs anything other than occasional xanax.

Unbelievable how eerie similar to my situation. Had to leave spouse of 30 years because the persecutory delusions got worse and worse and more bizarre. He became violent. Of course in this illness he thinks he is defending and protecting himself. He has no insight and doesn't believe he is sick. He remains unemployed, no support system, unmedicated. I believe cannabis could trigger it but the delusions don't go away now. Only meds will help. No hope for my ex spouse best of luck with your friend. The only help you can provide is to help convince her that she is sick. This is the biggest challenge for delusional people.