This is it -- the final confrontation against Thomas Magruder, the man whose greed has caused much chaos and death.
It took me a few times to figure out that you can't actually damage Magruder with bullets, thanks to that heavy armor he is wearing. What you need to do is throw dynamite at the geysers, so that Magruder gets hit by the blast. There is extra dynamite and whiskey scattered throughout the perimeter, so grab them when needed. Exercise caution when sneaking around, because if Magruder shoots Cole, it will hurt a lot.
Once his health is knocked down to about 30%, he'll retreat onto a balcony and attempt to shoot you down and take you out with dynamite. Some of his goons may appear on the opposite balcony, so take them out as quickly as possible. What you need to do here is take a shot at Magruder so that he throws some dynamite at you. Enter Quick Draw and shoot the dynamite in the air, and it will collapse the cave a bit. Once you do this enough times, the cave will begin to crumble, and that will be the end.
The ending and credits will be shown in the next video.