When she pretends so, we call it a "fake shifting".
Tommy's Mom: you can't, Tommy, you're depressed and I don't want you to kill yourself.
Tommy: that's okay mom, i'm not depressed anymore. I feel good, now.
Tommy's little brother: he's a liar, mommy! Look at the cut marks on his arms! He's still harming himself!
*Mom looks at the cut marks*
Tommy's Mom: why are you trying to lie, Tommy?
Tommy's little brother: that's because he's a fake shifter!