Lengthy but please bear with it

This is my first post here and I’d greatly appreciate any advice. Ok so I had a falling out with a close friend due to which cut off contact for about 2 months. After resuming communication, she told me that her "situationship" ( a guy she had started talking to a while before we had the fight) cheated on her with her own fake account (which her friend was texting from). She confronted him when he was on call with the "other girl" and he panicked and left the call. Later, he begged her and apologized profusely and she took him back after his older brother begged her and promised he’d make sure his brother behaves. I told her, like any sane person, to cut him off asap. She promised me she’ll do it once she feels like she can move on and will dump him when he least expects it to "hurt him" like he did her. I genuinely found it ridiculous that he was worth getting over but everyone has their own attachment levels so I said ok but by next month, he should be out of ur life. I warned her that if she’s not fast enough and he cuts communication first, she’d be the only one left to suffer. Fast forward a month and she’s completely out of it. After constant fights, he told her to leave him alone and blocked her from everywhere. Now she’s unable to sleep much and is bawling her eyes out and drowning in a miserable pile of tears over such a scumbag. She needs to focus on her uni/work stuff and is unable to do it, she’s lost her appetite and just doing really bad. Nothing I do and say can console her and she’s insistent on wanting to know why he did this to her, why he promised marriage and so on. She desperately wants to call him and yell at him and ask him why he did this to her but she knows he won’t pick up so she doesn’t call. The man didn’t even officially ask her out, I’m baffled how she got so attached in the short while we weren’t talking. I don’t want this affecting her health and career which she worked so hard for. I’ve tried telling her to distract herself a bit to stop obsessing over him but she says she has no energy for it. Please give any suggestions how to make this better for her, I’ve known her most my life and she’s never been so down. Seeing her hurt like this, and that too over someone like that, is heartbreaking and enraging, I just want her to be better. Please give any and all advice.