Adoption of a child please help?
It's expensive and there's a very long waiting list *if you're adopting an infant.* Couples who want a healthy baby wait 2-3 years on average and can expect to pay $25,000-40,000. But for an older child (particularly one who has been in foster care and become a ward of the state) it may not cost more than just fees to process the paperwork, if that. Sometimes families can receive stipends or special tax credits for adopting older children out of foster care, so the sum total may result in the adoptive parents paying nothing out of pocket. For everything else, your mother needs to speak both with the agency representing the girl in question as well as a family law attorney specializing in adoption. That's her best source of advice for adoption law specifically within the state of Texas.
Mom should hire a lawyer and also do her own research.
If a person wants to adopt a teenager, there are plenty in the foster care system in Texas who are legally free for adoption. She would contact the Department of Social Services and talk to a worker there about her next steps. Adoption from foster care is not expensive. In most cases, it is free.
So -- your mom wants to adopt a teenager, but has no idea how to do her own research or speak to a lawyer, but has to have her child do it for her? This would suggest that your mother has little education or motivation, and so would not be likely to be approved as an adoptive parent.
Good news! If your mother is adopting a teenager it would most likely be through the state Foster Care system and the cost is little to none. Your mother would need to contact the Texas Department of Child Services/Social Services/Youth and Family Services (whatever it is called there) and she could learn the process. In general, she would need to take some classes (parenting, especially parenting children that come from a traumatic background) and do some background checks and have a homestudy completed (which is to ensure the home/family is safe and stable). If the child is of a certain age, they do consent as to whether they are adopted or not. Usually, if a child was placed with you for fostering with the later possibility of adoption all parties know by the time it comes. If a family is searching for adoption and not fostering, there are multiple meetings (say, lunch with the family, child and social worker, a day outing with the family and child, progressing into overnight visits). If things go well, it can lead to adoption. As for Texas placement required, that would mean the child must remain in the state of Texas (rather than being adopted elsewhere). It could be because the child has other family connections that they wish to maintain.
Foster-to-adopt is free. Do that.