who do you love more....

....your gear or your brother?

another question from a different POV....

why don't you ask him to not keep his illicit substances in the house? (does he pay you rent and therefore have certain implied rights?)

if it's really an issue, he can keep his stuff outside in a common area, hidden away. maybe behind the BBQ or somewhere else close by where he can use/smoke it.

there's a solution here. just need to be creative