Need advice…HELP

I’m dealing with something with my sister and it’s been giving me a lot of anxiety. I’m not really sure how to handle it, and I mostly just need someone to talk to about it.

Basically, there’s this guy she used to talk to. They aren’t together, but she has become convinced that he’s stalking or monitoring her.

At first, I didn’t really know what to think. But then she started connecting different things to him. For example, she believes that songs he puts on his YouTube Music playlist are actually messages meant for her. She’ll look at certain songs or things online and interpret them as him trying to communicate with her.

It’s also become religious for her. She believes God is giving her signs or directly confirming that this guy is stalking her. Because of that, it’s really difficult to get her to consider that there could be another explanation, because to her it isn’t just a suspicion—she feels like God has confirmed it.

Then there’s a woman she found on social media who sells a book. From what I can see, the account looks like a normal woman’s account, but my friend believes this woman is actually the guy pretending to be a woman so that he can get closer to her and keep tabs on her.

What worries me is that all of these separate things seem to be becoming connected for her. Songs, social media accounts, things she notices online, and signs from God all seem to lead back to this same guy in her mind.

She has also talked about contacting him because of what she believes is happening, and that made me even more worried.

I don’t know if this is psychosis or something else, and I’m not trying to diagnose her. I just know this is very different and concerning to me, and it feels like it keeps getting bigger.

My uncle is coming next weekend and is going to try to help her get professional help. Until then, I’ve been extremely anxious. I keep thinking about her and worrying about what might happen before he gets here. I think I mostly need someone to listen because I’ve been carrying a lot of fear about this.