Ladies I need help , please !

Andrea
One of my good guy friends is in a really shitty relationship 
And he's trying to sort it all out, because he's unhappy
And he sees a lot in her that he dealt with his ex wife 
This girl doesn't want him talking to his friends
He can never do anything right 
She can't trust him for anything 
She's always blaming him for cheating 
Or having other girls 
Etc
She drives him insane always trying to pick fights over really dumb things 
But she turns around and posts on fb how much she loves him and she treats him like a king 
Etc 
I suggested he tried to be just her friend and for her to find someone whom she can trust since it can't be him 
But he'd be supportive because he wants her happiness 
But he's scared because she's told him that she'd go back to cutting herself and I think she said drugs also 
She seems really manipulative to me and i don't know how to help him out because i don't know what would make him realize she's hurting him 
And he deserves better..
Any advice would be great !!