How do i tell my parents?

im 17 and my brother is 19. he still lives at home and everything and has had a drug problem for awhile. he got addicted to meth when he was 13. he doesnt still do meth and hasnt for awhile, but he had a cocaine problem in the past and has consistently smoked weed. hes had behavioral problems and disrespects my parents all the time. hes gone to multiple treatment places, been in and out of jail, and each time he comes back home things never change. my parents set rules for him and they really care about him, but even after theyve kicked him out they always let him come back home. im sick of it. im sick of him. he doesnt want to change, and i understand that no one can make him change untill he wants to. im really reclusive about my feelings towards this but my parents know it bothers me. i just want him gone. i have a little sister who's 10 and i really dont want her to be around someone who's aggressive, disrespectful, angry and abusing drugs. hes selfish and manipulative and my parents are too soft on him. its been this roller coaster for so many years now and im tired of my parents stressing and tired of the **** he brings into our house. i know he's their first child and they dont want to give up on them but HE WONT CHANGE. i want to feel comfortable in my own home and i want peace again. i cant figure out how to tell my parents. ive told them things before but they just sigh and say, i know, its a mess, and complain over and over about how much he ***** up. they keep giving him chances even though hes run out years ago. i dont know what to do. ive built up this wall and this shell to keep me from caring. hes my brother but im over it. just because hes family doesnt mean hes not toxic. anyways. how should i go about addressing this problem? should i even bother? im afraid theyll just say "i know, i know" and thatll be the end of it. i dont know how to stress to them how important this is in my life.