DH's job is very flexable, so he can work from home for a few days if need be. Basically I know myself and I know him. If he hangs around at home and I am not on death's doorstep, he will just annoy me.
If I am sick, but ok to get up, shower, play and take care of the kids, but need to take it easy, play inside and quiet games, watch movies and have a nap....he goes to work.
If I am sick, can get up for 10 minute periods and have to lay down alot, he better be home early, but I can suck up and deal (and build lego while laying down).
If the only reason I get out of bed is to run to the bathroom (to do violent bodily actions) his butt better be home and it better keep the kids from jumping on me. I do the same for him.
If both kids are sick, he runs to the drugstore/grocery store before work, and comes home early. If they are both really sick, he stays home to help me out.
He doesn't have sick days at work. They have holiday time that they use as well as "discressionary days off". Basically a manager gives them a day off if they are sick....unless they are hungover