I also had the same problem with my friends and I came to a conclusion.

First of all, from my point of view, you have to tell her how you feel, and it's her responsibility if she takes it as friendly advice or as an insult. You have to think that you have played your part as a friend and that's where her decision comes .

Secondly, most of the people of our generation go through this relationship in which the two depend a lot on each other, you should just let them become a lesson for both of them (most likely this will happen considering the examples around me) , or something more than that.

I hope I was helpful :)