"Standing" means having the right to file an initial suit. You probably don't have standing (unless an attorney down there can help you establish standing under Texas Family Code 102.004). However, because the suit has already been filed, you can intervene in the suit.
If you can prove to the judge that the child's present living situation will almost definitely result in severe harm to the child's physical safety or emotional development AND that living with you is the best alternative, you can win.
You should know that these cases are extremely difficult to win. The U.S. Supreme Court and the Texas Legislature have made it more difficult than you can imagine for third-parties in general and grandparents in particular. Your ability to prevail is very fact dependent and we'd need many more facts than you can give on a site like AVVO in order to let you know your odds of prevailing.
I understand that folks come to web sites like this to get advice without having to pay an attorney, but some cases are so complicated that you just have to sit down with a GOOD family law LITIGATOR, pour out all the facts and how you can prove them, and get advice carefully tailored to your case.
Consult with an attorney in person. Grandparent standing (right to sue) is pretty limited. You'll need to discuss it at greater depth than is possible here.
This answer DOES NOT establish an attorney-client relationship. This answer is based on the limited information provided and is not intended to be conclusive advice. There are likely other factors that might influence or change the advice after a more lengthy consultation.
I am so sorry for your loss. As Ms. Lowery stated, grandparent rights are limited. Under the circumstances you described, you must act quickly and consult with an experienced family law attorney this week.
How did your granddaughter end up with the alleged father? .
You need to intervene in the paternity suit NOW. There are specific grounds for termination of his rights if he caused the death of the other parent. I am sorry for your loss.
This does not establish an attorney/client relationship. Dallas, Denton, Collin and Tarrant County, Texas practice area. Principal office located in Lake Dallas, Texas.