What if my friend found cigarettes and pot in his brother's truck?

ok so my buddy don't smoke he didn't relay know I smoke but he was like dude I found a bunch of cigs and cigars and grass in my older bros truck im friends with him too and I knew he smokes but my buddy is like what should I do I don't want to make my brother mad at me and he don't really have the guts to confront his parents about it and he cant say anything to his bro about it because he would just move out if anyone in his house found out so any advice would help

Wait...what?
How old is his brother?
If he's old enough (18), leave it be.

Walk away, and stop snooping in other peoples stuff

no it was my friends bro who came up to me asking for help with getting his bro to quit and I couldent realy answer him