There is a very delicate balance between a grandparent inserting themselves into a child, their grandchild, being disciplined by their son or daughter. And my recommendation is that you really allow your child, the parent, to be a parent and do the disciplining on their own. If you do have anything that you want to say, allow it to be done afterwards. And that goes for a husband and a wife situation as well, too. Don´t disagree in front of the child. Allow that discussion to happen outside of that, and even then it becomes very sensitive between the daughter, in my case, my daughter and my self. And so, one of the most beautiful things that you can do is allow your child to be the parent and then be loving to your daughter and supportive with her.