After the fire, he brakes down into tears because it suddenly strikes him that he has suffered a big loss.After a few moments, he realizes that his cat could not be seen anywhere and the thought of it that the cat might have perished in the fire makes him cry. He gave a new lease of life when it was a small kitten. Cat and the author are emotionally attached to each other. So it is a big emotional loss for the author.The simple thought of losing everything to that cruel fire breaks him down.
