Final answer:
Joy's illness in the text appears to be progressively getting worse, but there are moments suggesting temporary improvements.
The narratives also imply that illness can be a complex interplay of physical and psychological factors, which can influence the perception of an individual's health.
Step-by-step explanation:
In the various texts referenced, including Shadowlands, it appears that Joy's illness does indeed show signs of being steadily progressive, with her condition deteriorating over time. The excerpts provided depict various characters grappling with illness, and there is often an undercurrent of inevitability about the decline in their health. However, there are moments where improvement is hinted at or where hope is still clung to, even if these instances may be fleeting or may not lead to a full recovery.
For instance, in one narrative, despite a character's serious illness, there is a moment of consolation as another character insists on focusing on the present and hints at temporary improvement ('"Really, dear, you are better!"). This conveys that while there might not be a permanent reprieve from illness, moments of relative wellness can still occur.
It is also worth considering the mental and emotional aspects of illness, as suggested by the question about The Yellow Wall-Paper. Illness is not always a linear, physical progression but can also be influenced by psychological and social factors, which may affect how symptoms are perceived and experienced.