What imagery helps readers understand why Aunt Lupe's illness is so upsetting to the girls?

Imagery:

But I knew her sick from the disease that would not go, her legs bunched under the yellow sheets, the bones gone limp as worms. The yellow pillow, the yellow smell, the bottles and spoons. Her head thrown back like a thirsty lady. My aunt, the swimmer.

Hard to imagine her legs once strong, the bones hard and parting water, clean sharp strokes, not bent and wrinkled like a baby, not drowning under the sticky yellow light. Second-floor rear apartment. The naked light bulb. The high ceilings. The light bulb always burning.

Sometimes you get used to the sick and sometimes the sickness, if it is there too long, gets to seem normal. This is how it was with her, and maybe this is why we chose her.