This year I read an article about resignation syndrome. This happens mainly among children whose families hope to acquire asylum status. They sleep all day without eating, speaking and walking.
To tell you the truth, the same thing happens sometimes to children who are not refugees. I mean, you may already know such a child around you. For example, children who have trauma concerning big sounds start falling asleep when they feel tension before an altercation. Even if they start sleep, they feel numb and they are dissociated. Dissociation makes them appear to be good boys or good girls.
But many parents do not realize that, in fact, most parents are proud of their children when they appear to be good boys or good girls. If this rings true for you, your ego feels that truth is cruel. But in fact, only truth heals you.