Touch screen not responding

I'm certain my youngest son has changed the settings on a kindle. It was Woking fine until he got hold of it.

I have tried to reboot it but not getting any menu up

I've also charged it via wall and pc.

I can't drag the top bar down to get to settings. This has happened before and I double tapped the menu bar and it opened .

Is my theory right or is it a fault with the kindle

Thanks