He doesn't have anything to check on--no responsibilities unless they're foisted upon him. Even if he were heating a can of soup, he'd be more likely to let it boil over than to make sure it didn't. I base this on lack of any examples of him checking on anything and plenty of examples of him not being too engaged with the world around him unless riled up--and it takes a lot to rile him.
Here's one example I just thought of--even after being jumped by intruders in the beginning of the movie, his head submerged in the toilet bowl multiple times, threatened, his rug peed on, he didn't arm himself or prepare in any way when returning home in the future, or even enter cautiously. While he did attempt to block the door while inside, this was a vague attempt at prevention, rather than preparation. Checking on things is about trying to control the outcome, and he's not a controller. My take.