You can't forcefully pull a small child up by one arm. This may dislocate their shoulder and lead to serious injury - PSA to anyone who reads this.
What's up with this family? Has the emperor never had children? No. He has several children. How is it possible for him to be unable to communicate with children properly? And not just him, the maid, this Prince, the other maids too. Like wtf? You don't just tell a kid with scars that having scars lowers their value. You don't just get all angry and ask what's with that when you see scars. You don't just pull a small damn child by the arm angrily asking how they got the scars.
You. Need. To. CONNECT WITH THEM. Earn TRUST. Then ask. Obviously none of them have ever properly interacted with a child, or so it seems.