The ending of "Let's Get Invisible" was stupid

Usually they try and spin the ending to be bad for one of the main characters.

It's revealed (which was obvious at the time it happened) that the main character's brother was in fact the mirror image version when he last saw him in the episode (I mean before the ending). But at the end, when the Asian girl breaks the mirror and they all leave, the mirror fixes itself. Why would they have the mirror fix itself and give the mirror image of the brother a CHANCE to be put back in it like the black boy? They either should've gotten rid of the mirror image brother fiasco at the end, or removed the mirror healing itself.

A bright light can hollow the deepest of nothingness.