My grandson has been living with me since April of 2018. Both parents signed a motorized agreeme

You may not move with the grandchild.  If what was signed was prepared in accordance with Texas law for an Authorization Agreement for a Nonparent Adult Caregiver, the agreement should contain terms regarding how it may be terminated.  If your daughter or the father of the child follow those terms to terminate the agreement, you no longer have rights under the affidavit.  The Authorization Agreement does not give you legal custody of the child.  Even if your daughter does not follow the terms of the agreement regarding terminating the agreement, in my opinion it is clear she no longer agrees to the terms of the agreement and you should act accordingly.  If there are court orders in place regarding your grandson, then the custody terms in  the court orders are in effect. The parents may revoke the consent they gave you when they signed an affidavit, and it sounds like your daughter no longer agrees to the arrangement.  If you want to obtain legal custody of your grandchild, then you must do so through a lawsuit in court.