You need a lawyer. Today. Presentation of the kind of evidence you'll need takes skill. Use the find a lawyer button to search lawyers near you. Do not delay. Once your daughter gas been in the other state 6 months, it becomes her home state.
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 was about to post an answer to this question, then saw the comment where you said you had a lawyer. You should discuss this issue with your lawyer and, at this point, should probably refrain from posting details of the case on the internet. Remember that anything you post here can easily be found by the other side and potentially used against you in a hearing. You never know what the other side will say in a hearing and something you thought was an innocuous comment could be used against you.
Generally, no one piece of evidence will be enough to get a Judge to grant you custody. That said, it should be enough to get a Judge to prohibit unsupervised visitation between your daughter and her maternal grandfather. It does raise real questions about your wife's judgment and protectiveness. Contested custody cases are not simple matters. A lot of time and energy is put into developing and presenting evidence.
This does not establish an attorney/client relationship
In TX the Judge will always determine child custody issues using the "best interest of the child" test. the judge will look at the child’s emotional and physical needs, each parent's ability to raise the children, the stability of each parent's home, and each parent's future plans for the child. The court may also consider past or potential harm or abuse to the child perpetrated by the parents, as well as any evidence that suggests the an improper relationship between a parent and child, as well as the ability of both parents to co-parent the child; just to list a few thing. What you are going to need to do is show why it would be in the best interest of the child to live with you and why it would not be in the child's best interest to live with your wife. The past sexual abuse is a compelling reason but you should also mention why the child should live with you (such as a safe, loving, and stable environment). Additionally, if she has intentionally taken the child out of state and is refusing to bring her back without your consent that will reflect poorly on her ability to co-parent and should be brought up.
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