You probably won't read this, but when I saw that movie, my mother who was really not too different from the mother in that film, she had died some years before from some other but overall similar disease.

I had been laughing my head off until that point, but when his mother says, "I didn't want to be any bother," I started crying and just cried and cried through that whole scene you describe.

So I really feel for you. Have a virtual hug.

I have watched the film a couple of times since though. Once you know it's coming, it's just a pang.