The lawsuit is idiotic, and there is way more to this story.
If there was any reason for the mother not being able to care for the child, of course they would send her with the father. You do not belong the country you were born in, you belong to your parents, and a country would have no right to keep you in the US if your parents are leaving. Also, you expect the country to just support and pay for the child when you leave? the same child that you made, that is suppose to be only your responsibility?! It is disgusting.
The people filling the lawsuit are exactly what is wrong with immigration, and why people hate us and want to change the birthright citizenship.
Also, if the father just got deported and there was nothing wrong with the mother, then why would it take them 3 years to bring her back? Every child born in the US has a US birth certificate, and all you would need to do is hire a lawyer to do the paperwork and get a notarized permission from both parents and then somebody legal to bring her over to Texas with the documents.