Best friend is changing pls idk what to do cryin

She’s always been depressed and she’s extremely influenced by things she sees online (right now she’s into jirai kei) anyway now she’s hooking up with over aged men (we’re minors), talking drugs and smoking, making plans to do a double suicide, she also wants to be like Dolores from Lolita apparently. And now she’s talking about going back to her ex to do a double suicide with them.. who has moved on and is happy now!! It’s making me kinda grossed out but I also don’t want to lose her (I’ve already tried talking to her she just won’t listen she agrees but then does nothing)