@quick4 yo just take any powder , while going to bed (pour it in small bulk in circle,u hv to remember the pattern), pour it at entrance of the door and near ur bed and the walking route to ur bed from entrace. If ur brother was really doin that since the lights are off he will get caught by stamping on it he can't fix that powder when he scenes the powder,even if tries to fix he can't put in ur same pattern.u can catch him red handedly just teach him a lesson 😊.