Yes, her potential reaction has to be taken into account ~ and finding the right time is essential.
It's difficult, but sometimes, with friends you care about, who are not helping themselves because they are so immersed in negative feelings, you have to just be straight with them.
I think I'd say something like:
I hope that you trust me as a friend and know that I wouldn't do anything that I thought would be bad for you.
I know that you might not be happy about what I am about to say, but I care about you and I am very concerned about you.
You have indicated that you are not feeling happy about things and I feel that counselling might help you through this.
Why not just give it a try?
I'll even come with you, if you'd like me to.
Just promise me that you will think about it ~ please!
"The secret of success is constancy to purpose" - Benjamin Disraeli.