@awesome777yay I’m a guy, a father, and am divorced.
1) Are you 100% sure, that she was abused, or are you simply going off what she said? Was there any actual evidence of abuse taking place? Was there any documentation of any kind of any abuse? I say this, as a man that was threatened with a false DV by my ex wife with the intention of using it against me and gatekeeping access to our child. I am not taking sides etc…
2) Regardless of any allegations of abuse, if the man Fathered children, and is refusing to actively participate in raising them, he needs to be contributing to them financially. If your friend refuses to pursue this, it’s entirely on her. There’s free legal aid available, there really is no reason not to do this. If the man is indeed abusive as claimed, then documentation should show that he’s not fit to actually have custody of the children and if he does have access it would be limited at best, possibly under supervision again if there is documentation of abusive behavior etc…
3) The situation you’ve described is very disturbing, specifically her seeming obsession of being on dating apps while neglecting her children. She already has two children, they should be her primary concern, not ‘finding a new guy’. That should be waaaaay on the back burner.
4) You’ve described a situation where children are being neglected, a living space that’s not being properly cleaned/maintain. This is a sign your friend is struggling with some sort of mental health issue. This is not normal behavior.
There is no great solution to this situation. Your friend sounds like best case she’s either struggling mentally or, worst case she’s just a really shitty parent that’s putting her desire to ‘find a man’ in front of the needs of her children. Studies show that either of these situations are going to be very unfortunate for the children long term.
Honestly, I don’t feel bad for your friend as she’s an adult and sounds capable. I feel bad for her children, they’re innocent and have done nothing to warrant the living conditions/environment they’re in.