Your sister did NOT try and cut the cat's ear off.
She merely tried to give him a haircut (as demonstrated by your grandma on your head) with some scissors she absconded with, using her newly found mad chair-moving-and-climbing skillz. (Mommy has a better hiding spot now.)
She tried to give him a haircut and SLIPPED.
It didn't bleed much.
Ok, it bled a lot, but it was a nick. You can't even see it now.
Please stop telling the neighbors your sister cut off the cat's ear. Especially the ones that belong to PETA.
PS you'll not the stupid bugger still sleeps on her bed, he's obviously not afraid she'll gut him in the night. Squeeze him to death with love, yes, gut him, no.