Should I call CPS???

Hailey • Kinley Sophia was born in July 2015 and Theos Aiden born January 2017
My sisters stepsister has a 2 month old baby. She never has this child at all, she give him away to anyone in the family for days on end. She did some drugs during pregnancy and is still doing them and selling also. She is only 19/20. She and the father do not have jobs but just moved into an apartment which is paid for by the drug money. She posts pictures of her baby online and you can see the drugs and bongs in the back ground. Her mother and this girl do not think there is anything wrong with what's going on but everyone around her even family wants to call CPS. My sister said something and this girl flipped out and now doesn't want the family near her son but they have him now since she doesn't ever have him. Anyways I told them they need to call ASAP or something could happen to this baby boy. I don't want him to grow up thinking this is okay. I told them if they don't do anything about it I will. Should I call CPS or what??