How do you denounce your child's godparent?

Of course. If you want the preiest to act as a gogparent to the child, and if the priest agrees to being the child's god parent, then yes.

To assist the parents in their duties as Catholic mother and father. In practice, that means being as sign of the faith by what they say and do, how they act, in a sense a role model for the church....

No. The godparent must be a practicing Catholic, because their job as a godparent is to guide the child in practicing their faith. If the godparent isn't Catholic, then they can't fulfill their...

You don't. It was your parent's choice, not yours.

yes