I am about to kill my mother.

I am looking for a way to put this off as long as possible, and so I start watching one of the final episodes of the TV drama “The Americans.” Today, Keri Russell, playing a Russian agent , is spying on a State Department official by posing as a nurse for his terminally ill wife.

The agent is a stone-cold murderer, but she feels desperately sorry for the official, whose attempts to help his wife kill herself with morphine have left her in a gasping, not-dead limbo. So Keri Russell finishes the job by shoving a paintbrush down the woman’s throat and holding a plastic bag over her head.

This is not a good time to be watching this particular scene.

Right now my mother is in bed across the hall, in the endgame of Stage 4 lung cancer. She is nearly 83, she has had enough, and she is ready to die. More specifically, she is ready to have me help her die.

I can see her point.

An unsentimental, practical person, she has for many years been preparing for the moment when death would become more alluring than life. We have talked about it nonstop since she received her diagnosis about three months ago and, like Gloria Swanson going up in a blaze of grand pronouncements, declared that she intended to forgo chemotherapy.