If I Pray for a Person, Will God Intervene, Removing Their Free Will?

We have no way of knowing exactly what God will do when we pray for someone, but any interaction by God will not result in the loss of a person’s free will. For example, God may provide additional graces to help someone move closer to him (e.g. to entice him back to the Church), but the person still exercises his own free will in choosing how to respond to those graces.