Trying to help a friend who appears to be suffering psychosis

I have a close friend who is starting to appear delusional.

They have always been prone to believing in fringe theories and are quite distrustful of authorities, but as of late they have become extremely paranoid, convinced that they are being monitored in their home and followed around by nefarious people. They are also convinced that they are being electronically monitored all times. This has reached the stage of them being scared to sleep at their home and not wanting to stay in one place for any length of time. The internal logic of the story breaks down very quickly on examination but they get very angry and defensive if that is mentioned. They have been very reluctant to talk about this at all because they don't want to be labelled as crazy. I found out how serious it was when they asked to stay with me on a couple of different occasions.

The don't have any history of mental illness but they do have a physical disability which prevents them from working and has isolated them socially. The illness does mess with their sleep, for which they do take medication (but I don't know the details).

I am looking for some advice across a few different areas. I want to continue to be available to help and for them to speak to, and don't want to drive them away, but also don't really want to be encouraging the paranoia. I also am looking for advise on how I can go about encouraging them to seek professional help without alienating them. They are generally distrusting of medical professionals (of all kinds).

At the moment they see my home as a safe place, but I'm not really set up to have them stay full time and dont want to reinforce the stalking narrative.

Any suggestions of where I might look for advice are welcome.