Here’s a small sample of the kind of prayer you should be praying:
As the LORD lives, my kids (mention them by name) shall not come under the bewitchment of Harry Potter and his agents in Jesus’ name.
I bind all enchantments and divinations programmed to waste my kids in Jesus’ name.
The God that answers by fire let him be God. O LORD, answer by fire and disgrace every evil messenger assigned against my kids in the name of Jesus.
(this is an exciting one!) stamp the mark of “touch not my anointed” on the forehead of all your children. This will effectively put them out of reach of modern witchcraft influences.