What would you do ?

I have this friend well shr is now a over the phone coffee buddy because she moved to far away and also I don't have any more respect for her but I still talk to her because I want to make sure her kids are safe . See she has been with this guy who she had a baby with for 5 years she also has three other kids with two different dads ages 11,9,7&4 and she started off by telling me her boyfriend likes to tie her hands and feet up behind her back and duck tape her mouth shut and put X shape tape over her eyes to have sex he also wants her to acked like he's raping her she's supposed to scream and try to fight him this goes on ,on a regular bases he doesn't want to have sex anyother way oh and also sometimes puts a bag over her head anyways she don't like it but he don't care infact he likes the fa t she dont like it :( I told her either he is practiceing to r3ally rape someone or he has done it before that she needs to leave him but she tells me she loves him and blah blah blah but this isn't the worst part she also has told me she thinks he is touching her kids she tood me she walked in in her boyfriend watchung her 8yr old son taking a shower and punch her to get out so he ciuod finish and there was another insident where she was talking to her oldiest daughter in her room and her boyfriend came in wearing nothing to ask her a stupid question and all she said to him was get out I told her he was showing your oldest look your mom wont even do anything to help you and her youngest daughter who is 7 was taking a bath and told her that mommy your boyfriend makes it hurt down there I cried and bagged her to go to the cops she back tracked I wasnt giving up and so she gave me some bullshit stiry on how she called the cops and all the kids talked to them and theres nithing going on so I took it into my own hands and called the cops called social services told them everything and social services tild me I didnt have any proof that they cant just go to someone's house and acuse them of this I called none stop asked for supervisors and I got the same answer now im stuck with this shit on my contusios and I feel uselessi want to help them kids since there own mother obviously wont and im lost as to what else I can do :( and I make myself talk to this mother -monster everyday in hopes she will finally ask me for help getting her and the kids out but its been almost a year now and I dont see her going anywhere what would you do im lost and pissed with are social services department its there job and there not doing it .