My DSS is 15 and we're struggling to know how to deal with habitual lying. Often it's just small things (have you brushed your teeth? He'll say yes, when he hasn't, etc) But it's quite persistent. When asked just about any question he doesn't really seem to have any interest in giving an honest answer, just whether one he thinks you want to hear.
This weekend he ate an entire box of chocolates and then insisted he hadn't. He might have been hoping we'd blame one of the other teens, but as it happens they were all out so we're 100% sure it was him. He's really upset saying he's been "falsly accused" but I think just digging himself into a hole he can't get out of.
How can we help him not to lie so habitually? Or to find a way of backing down and apologising when he is caught out? Any tips?