You're holding a Lego as shown in the above picture.
But because the Lego is of poor quality, the blocks did not stick together and while you were holding the Lego, somehow it got separated as shown in the below picture.
Is it correct to say "the Lego got broken apart"?
The verb "break" is too much. It was just that the Lego blocks got separated. And a child may not understand the word "separated"