Edit: No, I watched it wrong.
Babies do scratch themselves by accident once their fingernails get long enough -- that's not rare.
Even if it were ghost, he's not necessarily to blame for the wound.
Spooky video though!
At the risk of being ridiculed for considering it a hobby, I've been ghost hunting/debunking bullshit for about 20 years after a few things I went through living on an old ass military base outside of Chicago. 99.999999% of these videos are mundane everyday bullshit that people see when they're expecting to see something paranormal, and confirmation bias makes them think it can't be anything but paranormal when in reality it's a speck of dust, a car driving by, or something else entirely mundane that shouldn't be given a second thought. If ghosts/paranormal activity were as common as TV makes them sound, everyone would have at least 3 spirits in their homes. It's telling that every time a story is shown on the news or on one of the various talking head "My Ghost Story" shows, the interviewees can barely pass for human themselves. Utter idiocy.
That being said, I think there's a scientific explanation out there for shit people legitimately do see, whether it's a time slip or a variation of the stone tape theory or something like realities intersecting. I know the things I saw could very well be me simply seeing another point in time for some reason or other. That's far more interesting than grandma coming back for a visit.