Calling CPS on a struggling single mom?

One of my son's friends mom is a single mother. She has 5 kids and works 12 hours and leaves the younger ones with the 17 year old cousin who lived with her and she has guardianship. The 17 year old dropped out of school so he could babysit the younger ones for her . The youngest is 2 months. There were already some red flags with her 17 year old nephew. I always got the vibe he wasn't mentally sound and one of his schools he was kicked out of for setting a teacher's car on fire. He's gotten violent with the kids. My son's friend is 10 and he told me he was sodomized by the 17 year old. Mom also knows this happened. I spoke to her and she claims she's already handled it. Handled it how because it doesn't sound like she called the cops and she still leaves them alone with him. She said she told him if that happens again she's putting him in a psyche ward. She didn't even take the 10 year old to the hospital because she works in the medical field and she tended to the injuries herself. Right now the friend has been staying the night. The mom told me that I don't get to judge her because she has no help. She has no village. She's doing what she can to get by. Her nephew did it one time. Then why keep having kids? She's old enough and has enough kids where they would tie her tubes if she wants. But she also pulled the postpartum card which A has nothing to do with B. Your nephew raped one of your kids. She didn't call the cops. She didn't get the 10 year old medical attention. The 10 year old is here but I don't know if he's doing it to the other kids plus there's a baby in that 17 year olds care too. I hate CPS. I get she has no village. I get she's a single mom