Provocative article. My mother fought against breast cancer for nearly a decade and at the final 4 months she really did start losing her facilities. Her liver was failing miserably and when she stopped taking medication her condition went on a nose dive. She would forget things in mid conversation (making numerous conversations feel like really dark renditions of the Swamp King and the Two Guards scene from "Holy Grail") and then she stopped speaking completely.
Eventually she really went into a "zombie" mode. Weird lesions started growing on her body (likely from her body being unable to properly filter things), her skin was pale, she lost most of her hair, she slept constantly, and then would often moan, groan, and cry as opposed to actual speaking. She lost full control of everything and really ceased to be a human being.
She eventually passed on Memorial Day of 2008. I obviously mourn her loss, and especially more now as I have since then gotten married and had a child, and I know she was really looking forward to becoming a grandmother one day.
Going through those dark periods was hard, but I was helped mainly by my future wife, as she lived in her own apartment and going there was a nice escape away from the horrors at home (mom had been put on hospice care there.) Sadly Left 4 Dead wouldn't be released for a few more months and it would take even more months for me to get around to playing it, but had it been around at the time I could definitely see it being a good stress reliever.