I'm sick of listening to her and telling her that he is a creep.
How can she not see?why is she being so thick?
I've name changed for this having posted here before about my experiences and seeking advicee.
I was in a near identical situation - not quite as bad perhaps in some ways (no suicide threats, public humiliation or drugs) but worse in others (he was married) - but I was utterly in love with a complete complete bstrd. Honestly, I still am.
When you say "why can't she see" - OF COURSE she can see. Of course she can. I knew I was being treated terribly. I knew he was using me for sex. I knew that I was letting him.
The thing was that I really felt powerless to stop it. It was like an addiction. It probably was an addiction. He triggered (and that is the right word) a response in me that was irrational but compulsive. He is highly manipulative and knew damn well how to push my buttons, say what I wanted to hear at the right moment.
Many many people told me I should get counselling or therapy about it - but I resisted - deep down believing this was some kind of love story and eventually he'd see the light, realise how much I loved him blurble blurb blah blah wurble wurble shit.
Many many times I deleted his number/went no contact/ found the strength to resist for a while (some times many months) but eventually I'd weaken - and like your freind end up in bed with him within 24 hours having not spoken to him for months.
The end point for me was when he dumped me yet again (if you can "dump" an OW) and I was sick of the cycling of it. It was making me very depressed and destroying my self esteem I realised I needed to stop it otherwise I would be still doing this when I was 60 and probably be suicidal.. So I decided finally to see some therapy. I know I am still vulnerable to him if he comes round again but have learnt techniques to protect myself. I hope I am better but the real test will be if he tries to contact me again in future.
Anyway to answer your question:
your friend knows full well he's treating her like shit
there is a small chance she is just using him for sex too but it is more likely he is triggering some reaction in her that means she is basically suffering from an addiciton
until she gets to the point she wants to help herself, there is nothing you can do
Please try and stay in the background of her life to be there for her. It will happen that she'll see the light but it probably won't be til she hits rock bottom.And then she'll really need you.