I caught my brother smoking what do i do??

I caught my brother smiking while he as on the phone in the garden. WHAT SHOULD I DO????? Should i tell my mum or confront him and tell him i’m worried about what’ll happen to him (Because i am after what i’ve seen in science). I’m 13 and he’s 17, alot of his friends smoke but i still dont know what to do. I don’t really want to tell my mum because he might hate me for the rest of his life and my mum’s dad died from smoking and she said she was always telling him it was bad for him :(. HELP!!!!!!!

Thanks in advance

Popular: Tips To Ensuring The Perfect First Date 5 Secrets for a Great Relationship Top 4 Foundations For A Great Relationship Top 5 Ways To Make Your Partner Feel Special This Christmas
More: I aplogized to this adopted kid in my house. he said alright? what does this mean? Help me urgent I'm stuck? Why did i think he was lying to me, what is wrong with me:/? She never replied, smh.. Why? When to contact my ex?