The black cat: The 3 passages

1) A reason of became a heavy drinker could be the sadness, because you're unhappy with your life or because someone died.

 

2) I don't know. It could be something to do with when he was a child. A similar cat, for example.

 

3) Everything the narrathor does is because he was drunk. All persons do something evil or estupid, it's normal, everybody makes mystakes