Do I have the right to hit or tell my little brother off?

My dad sometimes goes out for a few hour (no more than 3 usually) and when he leaves sometimes my little brother starts behaving like a **** and when i try and tell him to stop t he says "you aint dad so you can't tell me what to do" have i got a righ as the older bro to put him in his place? btw im 15 turning 16 and he is 11 turning 12