My husbands brother lives with us and he is a 14 year old. Well I suspect that he is smoking pot! My…

My husbands brother lives with us and he is a 14 year old. Well I suspect that he is smoking pot! My son went into his room and found a lighter and brought to me. Then I put the lighter in the kitchen and this morning it's gone again. + his room smells like a stupid amount of colons like he's trying to hide something.