Biological Mother Issues

So I am the step mom to my boyfriend's almost 2 year old son, I met his father back in October and even when we broke up from Jan to April, we didn't stop talking. When we were broken up, he had gotten back with his son's mother, but mind you, we are both the same age, I'm only a few months older than her, but anyways, when A.J was a baby to now didn't work, didn't earn an income, until now because she is pregnant and due in about two months with A.J's brother, from a different father whom she thinks she knows who is the father (this happened when she was pregnant with A.J, she didn't know who the father was since she was cheating, lucky it is my boyfriend's biological son, and no he did that get a test done, his son looks exactly like his father), but A.J's mother would hand him off to his aunt who he had known as his 'mother' since she actually took care of him and developed that bond, that his biological mother and him never had. Well, she had also left A.J in the car seat with throw up and soaked diaper and alone, she has done that in the house, she was on drugs after she saw A.J's father using drugs, but I have been in her son's life longer than her now, they had him taken away at 6 months old and his father has full custody of him, while she has visitation but supervised with him. I love her son more than anyone will ever know, plus I went to all but two court dates with my boyfriend to get his son back, she went to one court date that she was supposed to go to, but right before they broke up, h

e had fractured his foot and couldn't be on it, and it was weekend with A.J over, her 2nd time with her son , she told him that he and A.J we're too much (she had to get him up, change him, and get him ready for daycare), but here is messages of what we deal with. sorry for anything bad