Back story - friend (late 20s,2dc) met a guy last year and they had a 'relationship' for about 3 months. He constantly blanked her, told her he was on his way to see her then never turned up, didn't answer his phone and then arrived a few days later as if nothing had happened blaming the car or something trivial. He fucked her about daily. Turned out (as we all suspected apart from her) that he was in fact with someone else, living with her and her kids called him dad. A fairly serious relationship. He ended up having to choose between my friend and this other woman, he chose the other woman. Friend was devastated. She fell in love very very quickly and changed everything about herself to try and get him back but gave up and was only just starting to get over him when he turned up out the blue a few weeks ago. He got his daughter to message her saying how sorry he was etc and she fell for it hook line and sinker. Since then, he turns up at her house usually 2/3am, has sex, falls asleep then leaves the next morning. He blocks her so she can't contact him and then unblocks a few days later saying sorry, takes her out to the cinema then a few days later blocks her again. This has been repeated for the past few weeks and every time she's in a state, crying, not eating, not sleeping properly and constantly complaining to all of us about how she doesn't understand him or makes excuses for him. We are all fed up listening to it. He's so immature (in his 30s) and has absolutely nothing to offer anyone, no job, no house no fuck all but she's running after him like he's some sort of god with half a set of teeth. When he's treating her 'well' she's on cloud 9 and then days later she's back to reality.
We have told he repeatedly that he is taking tbe piss, he's using her and he will be laughing about this. It's giving his ego a stroke but she continues to let him in.
Any advice? What will make her listen?