Legal Question in Family Law in Texas

I don't know whether CPS is involved in the case. If so, that will be a complicating factor. But if there are no complicating factors such as CPS involvement, this is the easiest thing: She can sign a non-parent authorization agreement under chapter 34 of the Texas Family Code. The Texas Department of Health and Human Services has a free form you can use: https://www.dfps.state.tx.us/Application/Forms/showFile.aspx?NAME=2638.pdf

You could file a petition to terminate her rights and the father's rights and then adopt the child, but that is an involved process and is something you might consider AFTER you have possession of the child. Another option is once you have possession of the child for 6 months, you can file for custody, so to speak, by filing a suit affecting the parent-child relationship and ask the court to name you as the child's sole managing conservator.

The Chapter 34 route is easy to do, but she can undo it by revoking the agreement at any time. The conservatorship is harder to do, but it's also difficult for her to get out of it in the future, although it is not impossible. The termination/adoption path is the most difficult to do, but it cannot be undone.

Congratulations on the new baby. I know the circumstances are tough, but I hope you and the baby are a blessing to each other.