Dear God, I just read this. You think it's ok to beat a kid for what he did? Beating a kid isn't going to teach him respect, but it will teach him it's ok to beat someone, even those you love. You could beat my ass day long, but it wouldn't make me respect you.
What he did was wrong, absolutely, but why in the world would anyone put scissors in a place where a 7 year old kid could get them? For goodness sakes, it coulda been A LOT worse... he could have fallen on them and impaled himself! You said she was asleep, why would she go to sleep and leave a 7 yr old running around by himself??? That makes him, what... a 1st or 2nd grader, alone to roam the house and rummage thru places he shouldn't be in?
Sorry, but parents have to be more responsible with their lil ones. She's damned lucky he didn't end up hurting himself and end up in the ER, or worse.