Martin Pistorius in the story is a man who endured a long period of being locked within his own body due to an illness. He was someone who defied the odds as he slowly emerged from his non - communicating state.
Since I'm not well - versed in J J Fletcher's specific war novels, but in general, war novels might have detailed descriptions of military strategies. Maybe J J Fletcher's works also include such aspects.
I don't know exactly who J Andrews is in this story without reading it. But it's likely the protagonist or someone central to the events of the daydream - filled day.
I'm not aware of any extremely popular ones specifically about Martin getting hurt. However, popularity can be subjective. What might be popular among one group of fans may not be known to others. As I mentioned before, checking the major fanfiction platforms is your best bet.
In the fanfiction, Ally Martin could be an original character created by the author. She might be a witch or wizard with her own set of abilities and personality traits.
A key factor is a strong case for hardship. If the person can show that going back to their home country would cause extreme hardship, like in cases of political unrest or lack of proper medical facilities for a pre - existing condition. Another is having a valid offer of employment or study in the US that is in the public interest.