HELP I THINK MY BROTHERS A DEMON

like, actually, he angers me so much. i love my little brother, but its the shit he does that makes me SOO infuriated with him. like my mom bought us candy and he ate his AND mine even though he knew it was mine and it was my favorite candy. and when i caught him, he tried to lie about it and say he didn't do it and looked like i was the bad guy. but then he ADMITTED TO IT. there have been so many instances like this and he only cares about himself. i really think theres something wrong with him because as selfish as i may be, i would never even think about doing the things he does to me. please help,,, i may just kill the poor boy.