Sadly, no, the adult brother (and his adult friends) can all see the monster. It's a video blog affiliated with Slender Man.

I did go, hey, cutting metaphor. Especially given the visual of the cuts, which are down the arms and look like the cuts I used to make. I hadn't thought about molestation. Hm.

The kid finally got busted by one of the brother's friends, sneaking around with bandages. Friend went into the closet, saw the monster, dragged the kid with him into the hall, and threw a quick chain-lock (like you see in hotels) on the door. But they didn't vacate the house or inform their parents, who must not know!... but will see the lock.