It's kind of a mixed bag. Some aspects of Thor's character and story in Ragnarok are true to the comics, but there are also significant changes and creative liberties taken.
The movie Thor: Ragnarok draws its roots from the Marvel Thor comics. It weaves together elements from different comic issues to bring the story to the big screen. The comic influence is evident in the characters, settings, and overall plot of the movie.
The back story in the Thor Ragnarok trailer shows that Thor is facing a great threat to Asgard. Hela, the goddess of death, has emerged and is bent on destruction. Thor has been away and returns to find his world in chaos. He has to fight not only Hela but also deal with being stranded on the planet Sakaar. This sets the stage for an epic battle to save Asgard and its people.
I'm not very familiar with this specific fanfic. However, generally, a fanfic about Loki and Thor might explore their complex relationship in the context of the Marvel universe. If Loki is intersex in this fanfic, it could add an interesting layer to the character's identity and how they interact with Thor.
Thor might initially go into denial. He can't believe that Loki is truly gone. He may hold Loki's body for a long time, as if waiting for him to come back to life. Then, he could become angry. Angry at the situation, at whoever or whatever caused Loki's death. Eventually, he may find solace in the memories of Loki. Remembering the good times they had together and using those memories to move forward.
Friendship is also a big theme. Thor's relationships with characters like Hulk and Valkyrie are explored more deeply. In some fan fictions, they form even stronger bonds as they face new challenges together. There's also the theme of discovery. As Thor travels the universe, he discovers new cultures and powers, which is a popular aspect in fan fiction.
If Loki survived in Infinity War fanfiction, it could have led to a very different outcome. He might have used his trickery to deceive Thanos in some way. Maybe he could have pretended to be on Thanos' side while actually working against him. This would have added an extra layer of intrigue to the story as the other characters would have been unsure of his true motives.
Thor's perception of Loki would change drastically. Instead of seeing him as his mischievous but ultimately Asgardian brother, he would start to view Loki as an outsider, an enemy perhaps. This change in their relationship would affect Thor's self - confidence. He might become more hesitant in his actions, constantly wondering if he could have done something different to keep Loki in Asgard. Also, he would have to face the political implications within Asgard, as some might see Loki's stay in Jotunheim as a threat and put pressure on Thor to take action.