Henry would probably normally not be worrying too much about the sleeping habits or whereabouts of his friend, Wilson. Henry had just returned from his day in the woods after skedaddling at the first shots of the second Confederate attack. He had been clubbed in the head by a fellow Union soldier and had just made his way back to camp. He had been greeted by Wilson, who was the sentry on duty. As the corporal led Henry back to the campfire to tend to his wound, Wilson called after him to
"Put 'im t' sleep in my blanket, Simpson. An'—hol' on a minnit—here's my canteen..."
Wilson gave up his own blanket and canteen for Henry to use, since he thought Henry had been wounded. That's why Henry was asking his friend where he would be sleeping on this night.