In this fanfiction, Luffy might be used as a bargaining chip by his captors. Maybe they'll try to exchange him for something valuable, like a powerful Devil Fruit or a large amount of treasure. His crew would then surely launch a rescue mission, facing many challenges along the way.
Well, in the 'big mom is luffy's mom fanfic', they might have crafted a story where Big Mom is Luffy's mom. But it goes against what we know from the official 'One Piece' story. Fanfictions like this can be really interesting as they can rewrite the story in unexpected ways. They might have some interesting plot twists and explanations within the fanfic to justify this relationship, but it's not part of the main 'One Piece' universe.
One possible plot implication could be a change in Luffy's power source. Since Big Mom has such unique and powerful abilities, Luffy might inherit or be related to some of those powers in the fanfic. Maybe his Devil Fruit ability could be related to Big Mom's in some way.
The outcome is kind of ambiguous. Luffy shows great strength and determination but doesn't defeat Big Mom completely. The battle has many twists and turns that keep you on the edge of your seat.
Rayleigh would be a great candidate. He's an experienced pirate and has already trained Luffy for a while. He has a lot of knowledge about the world of pirates and could give Luffy a talk about the deeper secrets of the Grand Line or how to deal with the powerful enemies that lie ahead.
As of now, in the manga, the identity of Luffy's mom remains unknown. There have been many theories and speculations among fans, but no official confirmation.
It could be about Luffy having an important conversation. Maybe it's about his dreams, his crew, or some kind of revelation he has. Without reading it, it's hard to say exactly.
I'm not sure if there is such a specific fanfiction. There are a vast number of fanfictions out there, but this particular concept might be quite rare or not in line with the general tone of the 'One Piece' series. Fanfiction often explores different relationships and scenarios, but this one seems rather out - of - the - ordinary considering the nature of the characters in the original work.
In a 'naruto gets captured' fanfiction, he might be tortured for information. His captors could be after the secrets of his Nine - Tails chakra. They may try to use him as a bargaining chip against Konoha.