I think if you're truly a friend you should communicate that his behavior frightened you, seemed wildly out of character, and you're worried he needs medical attention or at least therapy. If he can't understand that and won't get himself examined, you definitely need to look out for #1 and ghost. Even if he's got some medical/psychological issue, a break in the relationship is necessary for it to be corrected.
Someone else's utterly inappropriate, aggressive behavior does not create an obligation for me to do something that might put me in more danger.
If the OP wants to communicate with him, that's dandy. But if she feels fearful about doing so, he's the one who broke the social contract with his behavior. If he did that because he's ill, that's unfortunate. But it doesn't change the fact that she could very well be increasing the danger to herself by addressing the situation with him.
You are correct. You don’t have an obligation to do shit and neither should the OP - if the person is not a friend. I’m happy to tell random strangers who are rude and aggressive to fuck off or ghost on them or even kick their ass if I have to. But I make special allowances for friends. If I’m so threatened by a friend I’ll make have someone back me up when I gently mention that, as a friend, I’m concerned about their mental health. It might save their life. Hell, it might save other people’s lives.
I suppose you’re not obligated to do that for a friend either. But that leads to the question: Are you worth being friends with?
Eric, you are a man. This former friend is a man. Cassie is a woman, which means she is physically more vulnerable to this former friend. Please notice that all the posters pointing out the dangers and suggesting ghosting him are women. Maybe we are seeing things in this situation that you are not? As in, he is a potential danger to her? And he broke the social contract first.
What I'm seeing is you putting out a double standard. This is the era of the strong, independent, smart woman. Of feminism. Except when it comes to being an adult and being a friend. Then women are small, frail, emotional creatures that need to be put on a pedestal one moment, protected another.
Maybe I'm not seeing something. Maybe he collects hockey masks and machetes for a hobby. Or that he's not really a friend but an acquaintance she calls a friend because she likes his dog better. In either case it's just not worth it to stick around and she should just ghost. But she asked and she called him a friend. So I fell back on what I'd do for a friend not as a man but as an adult and as a person who values friends. Again, there are ways to do this without the OP sticking her head in the lion's mouth. Nor is she obligated to "cure" him or, as I pointed out, even hang around while he cures himself.
It's not putting women out as frail and weak to say, "you don't own risking your safety to anyone who has behaved wildly inappropriate. You don't have to be the nice girl if you feel there is risk in doing so."
That's a risk of empowerment. For me, where the male/female dynamic comes in to place is that some men do feel entitled to a woman's attentions and will absolutley snap whtn they don't get it. As such, it's something from which women need to protect themselves.
This guy is not her friend. He stopped being her friend WHEN THE THREW A KNIFE!
You are throwing out these glib comments about not confronting him while he's holding a weapon. The entire point is that if he doesn't take it well, he can find her at any time. It's not as though he disappears from existence so as long as she is safe when she addresses him, so he could never be a threat to her again.
Are you aware of some of the interesting research on restraining orders? (No, I'm not going to go dig it up, even though yes, I am citing it.) Many experts actually recommend NOT getting a restraining order because once someone has snapped to the point of violence, it's not especially likely that the threat of an additional charge of violating an order of protection is going to be a deterrent. But the act of receiving a restrainign order can absolutely enrage them and make things worse.
Addressing his behave is, in some ways, comparable to getting a restraining order. Sure, it could make a rational person say, "Oh shit, I really have been behaving badly and need to stop". Or if could make someone who is already unstable feel humiliated, insulted, and rejected. Not a good combo. Even if he's not clutching a chain saw at the moment of the conversation.