is this child abuse ? if so should i call cps ?

my neighbor lives with her 5 kids at her moms house after losing her house because of her unstable relationship with her ex , he was abusive towards her infront of the kids , the kids ages are 15, 10 , 9 , 6 and 4 . since the mothers boyfriend was abusive the kids got taken away from her twice before and put inhome with their grandmother because they saw him beating her , calling her names , trying to break her fingers and choking her . in order to get her kids back she had to break up with her boyfriend , she told cps she did and got the kids back even though she didn't she was still with her boyfriend . its been 4 years since this happened and since then they still live at their grandmothers house . she refuses to get a job , sleeps all day and treats the kids badly . she calls the kids fat , ugy , worthless , a h** , a s***stupid , good for nothing , b**** , a** hole , a peice of s***and other names . she also tells them that shes gonna kill them and wishes them dead . she sometimes hitd them , shes even tried to choke the 4 year old , and since she wants to sleep all day she forces the 4 year old to stay in the room and not to leave until she says so . she makes the kids cook for her and clean for her . before they moved in with their grandmother she use to make the 15 year old (who was 12-13 at the time ) cook for the kids , get them ready for school , get them ready for bed , help them with their homework and clean the house .
the reason no one has called cps is because theyre all afraid of her even her mother whom she is also mean to . she says she is going to kill them , all of the kids want to get away from her but theyre scared to be separated from their family , the 15 year old has tried to kill herself and is self harming because of her mother I'm afraid either the 15 year old is going to kill herself because of everything or the mother is going to kill them









this has nothing to do with this but she recives checks for the 15 year old because her dad died and she uses mostly all of it on her and her boyfriend