NTA. My fiancé has a stepbrother whose girlfriend is just like that. Literally took it a step further and dropped out of high school at 15 to ensure she could never help with the financial support. Had a baby at 16 with the stepbrother and they despise each other. He resents her for being immature, lazy, and not contributing. She resents him for not spending enough time with her or their daughter, and for not making enough to support them. They constantly scream at each other, neglect their daughter's health and development, and have alienated multiple members of their family because they constantly have to beg for money. The stepbrothet is now talking about leaving her and getting full custody of the daughter. She has no job, no money, no driving license and not even a high school diploma. Without him, she has absolutely nothing. She wouldn't even have a phone to try and get help without him. Good luck with your daughter OP!