Grandparent adoptions?

ok my parents adopted my daughter 10yrs ago since i made some mistakes, she is now 16 and is wanting to come stay with me for a semester of school to see if she can do better, and get away from some bad stuff, my parents have no problem with it but her other gma is having major issues with it and is threating to call CPS and have her yanked out of there, if this other woman gets her i will never see her again, what can we do?