Gray would be devastated. He might go into a state of deep depression, isolating himself from the rest of the Fairy Tail guild. He would blame himself for not being able to protect her, especially if her death was related to her love for him. Gray would probably be filled with anger as well, and he would vow to take revenge on whoever was responsible for her death.
In some Fairy Tail fanfictions where Juvia dies, it could be a very emotional and impactful scenario. It might be due to a powerful enemy she couldn't defeat, sacrificing herself to save Gray or her friends. Her death could lead to Gray's character development, making him more determined to fight against the forces that took Juvia from him.
Well, it could make Gray feel an extreme sense of guilt. He might blame himself for not being able to protect her. And this could lead to him becoming more withdrawn and brooding, perhaps even pushing away his friends as he grapples with the loss.
One possible scenario could be Juvia sacrificing herself to save Gray. In the heat of a battle against a powerful enemy, Juvia might use her water magic to shield Gray from a fatal attack, but at the cost of her own life. Another could be that she succumbs to a dark magic that she was trying to fight off alone, not wanting to endanger her friends. Maybe she gets caught in a cross - fire between two extremely powerful magic users and her body is too weak to withstand the impact.
One possible reason could be self - sacrifice. Juvia might give up her life to protect Gray from a deadly attack. She loves Gray deeply, so sacrificing herself for him would be in character.
In a 'Juvia Gets Drunk' fanfiction, Juvia would most likely interact with the members of Fairy Tail. She might start bothering Natsu, asking him silly questions like if he can really breathe fire while drunk. She could also interact with Happy, and they might get into some sort of funny exchange, like Juvia trying to teach Happy a new song she made up in her drunken state. And of course, she'll interact with Cana. Cana being the drinker she is, might find Juvia's drunk behavior either hilarious or relatable and they could have a long chat about different kinds of drinks.
The relationship can start with mutual curiosity. Naruto is curious about Juvia's magic and Juvia about Naruto's ninja abilities. They begin to exchange knowledge, which brings them closer.
Their relationship would likely become more serious. They would have to think about not just themselves but also their baby. There would be more commitment and responsibility between them.