He was standing at the front door, but watching the cat sitting on the rocking chair. It was black and white and looking out onto the green grass, or above the apartment complex, or beyond it, at the place his mother was, somewhere. He didn't have to jiggle its handle to see if the door was locked, to know if you weren't home. But he had locked you out of his heart for so long by then, that hating you for locking the front door would have been ludicrous. He was just tired, not only from a long day at school, but also from asking the neighbors for a bite to eat. The cat flicked its tail in drowsy agreement. It never came in, but he never tried to make it come in anyways. By then it was too late to care about cats in rocking chairs.
The perspective in this poem might confuse some, so I'll elaborate just in case it does. The person at the front door is actually the son, and the yours and yous in the poem are adressing the father.