A great fanfiction idea could be Luke getting hurt while on a dangerous mission to save a planet. He could be poisoned by an alien creature. His friends then have to race against time to find a cure, and the story would show their loyalty and Luke's own will to survive.
Some fanfictions might involve Luke getting hurt because of a betrayal. He trusts someone, perhaps a new ally, and they end up turning on him. This not only causes physical harm but also a great deal of psychological damage. He then has to figure out how to deal with this betrayal while also trying to stay true to his Jedi values.
Imagine Luke is hurt when he tries to explore an ancient Jedi temple that has been corrupted by the dark side. There could be traps and dark energy that harm him. His journey would then be about not only healing his physical wounds but also purifying the temple and restoring the light side within it.
One possible fanfiction could be about Luke being abandoned on a desolate planet as a child. Maybe he has to fend for himself and discovers his Force abilities on his own without the guidance of Obi - Wan or Yoda at first. This could lead to a very different journey for him, perhaps making him more independent and distrustful of others.
There could be such a fanfiction. Fanfic writers like to explore different facets of their favorite characters. In the case of Luke from Star Wars, his not eating could be a plot device. Maybe he's on a dangerous mission and has no time to eat, or he's in a state of distress and has lost his appetite. This could lead to an exploration of his character, his relationships with other characters who might be concerned about his lack of eating, and how he overcomes whatever is causing him not to eat.
One possible fanfiction could involve Luke Skywalker being forced into a life of thievery due to some extreme circumstances in the Star Wars universe. Maybe he has to steal to survive on a desolate planet or to obtain crucial information that the Jedi Council or the Rebellion needs but can't get through legal means. He might use his Jedi skills in a stealthy way to carry out these thefts, like using the Force to move objects without being detected.
A fanfiction could revolve around Bard being mistaken for a Jedi by Luke Skywalker at first sight. Bard, confused but adaptable, goes along with it. As they journey together, they learn about each other's cultures and beliefs. Luke tries to understand Bard's connection to his own world's powers while Bard is in awe of the Force. Eventually, they become great friends and fight side by side against the forces of evil in the Star Wars universe.
One possible fanfiction could be about Leia and Luke going on a secret mission together. Maybe they are trying to uncover an ancient Sith artifact that could potentially destroy the galaxy if it falls into the wrong hands. They would use their unique Force abilities, Leia's diplomatic skills and Luke's Jedi training to outwit their enemies.
In fanfiction, a 'spacer' Luke Skywalker could be on a mission to spread the teachings of the Jedi across the galaxy. He'd use his starship to journey to various systems, facing challenges from pirates or the remnants of the Empire. His experiences as a spacer would shape him into an even wiser and more powerful Jedi.
One great 'Star Wars Luke Fanfiction' is 'A New Hope: Luke's Journey Beyond'. It delves into Luke's further adventures after the events of the original movie. Another is 'Luke Skywalker: The Lost Years' which fills in the gaps of his unaccounted - for time. And there's also 'Luke's Force Awakening', which imagines his role in the new era of the Star Wars universe.
One idea could be that Luke is sick due to a strange alien virus he caught during a mission. His friends in the Rebel Alliance have to search for a rare antidote while also protecting him from the Empire who might try to capture him in his weakened state.