Why was Mr Jones drunk on the day of the animals' rebellion, and why didn't he care about the animals in Animal Farm?

We learn that Mr. Jones started drinking because he was depressed after losing money in a lawsuit. The heavy drinking led him to neglect the animals on his farm. He would "lounge in his Windsor chair" in the kitchen for whole days, reading newspapers and guzzling alcohol. His farm began falling to rack and ruin from neglect, and the animals often went hungry.

On the eve of rebellion, Mr. Jones, apparently still upset over his lawsuit, had gotten so drunk at the Red Lion pub that he stayed out all night and didn't return until the middle of the next day. His farm hands failed to feed the hungry animals, and when Mr. Jones got home, he went to sleep on the sofa rather than check on the animals' welfare. By evening, the animals were still unfed. When the hungry beasts couldn't stand it any longer, they broke into the grain bins and started to eat. Mr. Jones and his men arrived with whips, but the animals rebelled. They butted and kicked, frightening the men, who fled the farm.