There isn’t many things that get Luffy down but since Aces death, he’s been a lot more conscious of the idea that people close to him can die. And when he sees you of all people, suffering and sick, it tears his heart into a million pieces. How is he supposed to be pirate king without you? Luffy might not be the best boyfriend at times due to his immaturity but he would never ever leave your side. He did everything to help nami and he will do the same for you.