Thanks

Do your best to teach him about honesty. How it affects him and those around him. If you catch him in a lie make him admit to it so he knows. And some sort of punishment if he can't accept that it's wrong. But also creating a safe environment with you or both parents that doesn't make him feel like he has to lie to avoid getting punished or in trouble. My niece used to lie a lot. Good luck.

Lol I wish that would help

Trick him. Say if you lie you loose an eye lol

No. My 12 year old brother lies all the time.