What To Do About My Annoying Little Cousin?

Im 12 And He,s 8 We Are Both Boys He Was Supposed To Spend tHe Night over My House For Only 2 Days But Now He,s Spending Like 2 Weeks And He Is So Annoying And Dumb And I Literally Mean Dumb Today He Told Me That My Mothers 28 Year Old Sister Was My SIster So I Told My MOther To Tell And She Told Him That She Was,nt My Sister And He STill Would NOt Listen And THen He Messed Up My Room And Would,nt Even Help Me Clean Up He JUst Sat There And Watched TV So I Put Him Out Of my room But My Dad Made Me Let Him Back In And I Stay Up Til 6:00 AM Every Night And When I Finally Fall Asleep 2 HoursLater He,s In My Room Bothering Me And Wont Let Me Sleep And My Mom Does,nt Care All She Says Is " He Wants To Play With You " But I Trying To Sleep And He Is Very Destructive And Wont Leave Me Alone I Cant Even Maturbate For Gods Sake!!! He Constantly Follows MeEVerywhere I Go Asking Me Stupid Questions Even The BATHROOM!!! I Have To Hurry Up And Run In There And Lock The Door So He Cant Get In And My Mom Just Will Not Listen And I Canot Stand Him I Want Him Out Of My House What Do I Do With This Little annnoying Bastard!!!