I think this guy is nuts.

I can't tell for sure what knife he's using but it doesn't look very large for what he's trying to do.

That's a little hog. A little knife, too.
I make knives for guys who have to have a 10" blade to make sure they can reach the heart at a bit of an angle.

I got the video from an old BladeForums thread.

Small hog or not I was intrigued by the small sized blade he was using. Also by the fact he didn't go for the heart but slit its throat? I also got a chuckle when the boar charged and he took to the water.

I've been going through the videos you suggested in the pack knife thread and am very impressed with your quality and design.

Correct. The fact that he could manhandle the hog and slit it's throat suggests they're dealing with smaller sized animals.
You go for the heart on the dangerous big ones!
But don't let me minimize his accomplishments.
He can actually say he "brought home the bacon".