Straight from the source.
https://www.oag.state.tx.us/elder/grandparents.shtml
In Texas, a court can authorize grandparent visitation of a grandchild if visitation is in the child's best interest, and one of the following circumstances exists:
The parents divorced;
The parent abused or neglected the child;
The parent has been incarcerated, found incompetent, or died;
A court-order terminated the parent-child relationship; or The child has lived with the grandparent for at least six months.
So it sounds like if you are in an intact family and none of the situations mention above exist, the grandparents are SOL...