Yup, toddlers have no need for political clout or intrigue. Her calling him out publicly is the most honest accusation possible.In this case, I disagree. The whole point is that he's cleaned his tracks.
So do things the opposite way. Openly accuse him with a child's testimony. It can't be refruted by proof, and the mere fact that the accusation was made makes it incredibly unwise for other nobles to support him.