Suggest a slightly modified plot for "The Catcher in the Rye" to make it more compelling, while preserving other qualities of this book

In an alternate version of "The Catcher in the Rye," protagonist Holden Caulfield is not merely a troubled teenager wandering the streets of New York City, disillusioned by the phoniness of the adult world. Instead, this narrative introduces a compelling twist: Holden has a younger sister, Phoebe, who is seriously ill. This crucial plot element adds an underlayer of urgency and purpose to Holden's journey.

The story begins as the original does, with Holden being expelled from his prep school. However, in this version, his immediate concern upon leaving school early isn't to avoid his parents’ disappointment, but to spend time with Phoebe, fearing he may not have many more opportunities to do so. The depth of his affection for Phoebe and his fear of losing her contrasts sharply with his cynical view of the world, adding layers to his character and making his disdain for adult hypocrisy even more poignant. He sees in Phoebe a purity and innocence he believes is worth protecting at all costs, fueling his fantasy of being "the catcher in the rye."

As Holden wanders through New York City, his escapades and reflections are tinged with this added dimension of familial love and fear of imminent loss. The various encounters he has – with former teachers, nuns, old acquaintances, and strangers – are colored by his internal struggle between maintaining his connection to childhood innocence through Phoebe and facing the inevitable realities of adult life, which he views as fundamentally corrupt and devoid of authenticity.

Holden's visit to the Museum of Natural History becomes even more symbolic; it's not only his own childhood he wishes to preserve in amber but also Phoebe’s. His later decision to run away and live a reclusive life, inviting Phoebe to join him, stems from a desperate attempt to save her not only from the physical illness that threatens her life but also from the metaphorical diseases he perceives in society.

In the climactic carousel scene, as Holden watches Phoebe ride round and round, his realization deepens. The beauty of the moment lies not in preserving Phoebe in perpetual innocence but in allowing her the freedom to grow, change, and even fail. This moment of clarity brings a more profound conclusion to Holden's journey, portraying not just a young man's cynical view of adulthood but a poignant narrative of coming to terms with the complexities of life, the inevitability of change, and the power of letting go.

This modified plot preserves the fundamental essence of "The Catcher in the Rye" – the alienation, the struggle with identity, and the critique of societal norms – while adding a layer of emotional depth and narrative drive through the looming tragedy of Phoebe’s illness. Holden is not just a disaffected youth but a brother grappling with looming loss, making his journey a universally resonant story of love, fear, and the painful process of growing up.