Well, his parents might be a bit shocked at first. I mean, Luffy's crew is full of such unique characters. They could start by testing the crew's loyalty to Luffy. And then, they might offer some valuable advice or even some special training. Like, if his father has some unique skills, he could pass them on to the crew to make them even stronger for their future adventures.
Most of the crew would be excited to meet the people who brought Luffy into the world. They would see it as an opportunity to understand Luffy better. Chopper might be a bit shy at first but would soon warm up and start asking a million questions about Luffy's early life, like what kind of diseases he had as a kid or how he grew up so strong.
They would probably be very surprised at first. After all, they might not have expected to ever meet Luffy's mother. Then they would be excited to learn more about Luffy's past from her.
Luffy, of course. He and Sabo have a deep history. They grew up together and Sabo was like a brother to him. Their reunion would be filled with joy, hugs, and probably a lot of tears. Luffy would be over the moon to have Sabo back in his life and on his ship.
Well, if the Luffy crew were to meet his mother in fanfiction, it could go in many ways. For one, she might be a strong pirate herself. She could then train the crew in new fighting techniques. Or perhaps she has connections all over the world of One Piece and could introduce the crew to important people. It would surely strengthen the bond within the crew as they learn more about Luffy's family.
Obviously, they will support Luffy all the way. He is their captain, and they have complete faith in him. They have been through so much together, and they know Luffy's strength and determination.
In such a fanfiction, Naruto might be overwhelmed with emotions. He could finally get to understand the sacrifices his parents made for him. His father, Minato, might share some of his jutsu secrets, and his mother, Kushina, would probably embrace him tightly, telling him how much she loves him.
It could put them in a lot of danger. The World Government would target them. But it could also strengthen their bond as they face the challenges together.
In a 'Sabo meets Luffy crew' fanfiction, there could be a lot of emotional reunions. Sabo might share his adventures since they last parted. He could train with the crew members, especially Zoro to exchange sword - fighting skills. And he would surely have a great time reminiscing about their childhood with Luffy.
In this fanfiction, Luffy might be initially in awe of Whitebeard's presence. He could challenge one of the crew members to a friendly spar, like Ace perhaps. And they might share stories about their adventures at sea.