How to handle friend's religious and spiritual ranting?

[Leporidae]

I have a dear friend that I known for years. We share a hobby and some interests and we have a good time talking about those. The problem is, that she will often randomly start talking about religious and spiritual things. I'm an atheist and have told her before that I'm not interested in religious books and talking about spiritual dreams and stuff like that. I will listen and try to understand, but often what she says makes no sense. She sometimes catches herself not making sense and says that these subjects are too hard to explain. Even if I tell her sorry, I'm not into this topic, I don't know about religious author X or Y, try to change the topic and clearly show disinterest she keeps talking at me about it. It takes a long time for it to sink in that this convo is not wanted and is over.
She has struggled with bad mental health in the past and I have strongly urged her to seek help, although she has been very hesitant because she believes that some of her symptoms are messages from the heavens. As a non-believer, I can't help but think that all of this is connected to her mental health.
I don't want to be harsh with her as she is a vulnerable person who has had friends drop her before because of her spiritual word salads. I don't want to let her down too, I care about her. WWYD?

It also unsettles me because I grew up with an abusive, mentally ill religious parent. My friend is not like that though.

Bumping, maybe it would be better to post in Relationships?
Or does anyone know where else I could get advice about this? I'm often concerned about my friend's mental health (she starts to isolate herself, does not keep up hygiene, is depressed and sometimes scared because of her visions) and I don't know how to best handle it when she starts to talk about her religious ideas which I don't share or when she starts to talk in a way that doesn't make sense as I suspect it has to do with her mental health.

I cant help but bumping for you in the hope that someone can help.

Is she involved with mental health services at all? If so, could you contact the local community mental health team and express your concerns? They won't be able to give you any info on her, but you should be able to flag it with them.

If she's not involved with mental health services, do you think she might come with you to the GP?

Is she a member of a particular religious organisation like a church? If so, you could raise your concerns with her spiritual leader or the organisation's safeguarding person. Your friend might be more willing to accept help if her religious leader suggests it, and they might know of counselling that's both BACP accredited and understands her religious framework.
Most mainstream religious groups wouldn't want visions to leave someone terrified and would be concerned if someone wasn't able to look after themselves. I appreciate this doesn't help if she isn't operating within any particular religious tradition though.

Yes, it might be so bad that contacting a mental health team is the way to go. I realize more and more how just serious her condition is. I need to set even stronger limits with her weird religious talk too, I fear I'm just enabling her otherwise.