I'm not sure if there's a mechanic that makes him wake up when people loot the chests, but it's a little annoying to kill the giant and discover someone looted everything. Maybe give the giant most of the good loot on him?
I remember fighting him and he had some decent loot on him, though that might have been luck, more than anything else.
Keys are also a good way to do it. The troll hag random is another one where people stealth or invis past it to loot the area then leave the enemies behind.