In the 'ichigo gets kidnapped fanfiction', he might be rescued by his friends. For example, his comrades from the Soul Society could sense his distress and come to his aid.
There could also be some side characters from the original series that play important roles in the 'ichigo kidnapped fanfiction'. For example, the shopkeeper Kisuke Urahara might show up with his knowledge and resources to assist in the rescue. His assistants, Tessai and Yoruichi, could also be part of the story, adding their own unique abilities to the mix.
I think his family would be the first to help. His sisters could bring him cold compresses to reduce the fever, and his father would use his medical skills. And from the Soul Society, Renji might come to check on him, as he and Ichigo have a sort of friendly rivalry. He would want to make sure Ichigo gets better soon so they can have their next sparring match.
In many fanfictions where Gil gets kidnapped, it could be for various reasons. Maybe it's by a rival group who wants to use him as a bargaining chip against his friends. For example, in some stories, Uma's crew might be targeted because they are seen as a threat in the Isle of the Lost. Gil, being a part of that crew, gets kidnapped. Writers often use this plot device to create drama and show the loyalty and courage of the other characters as they try to rescue him.
Ichigo would also experience a period of sadness. He values his relationships, and when one is broken through betrayal, it would hurt him deeply. He might isolate himself for a while, brooding over what happened. But ultimately, he would use this experience to become stronger. He'd learn from it and be more cautious in future relationships, while still maintaining his core values of loyalty and trust.
In some 'ichigo kidnapped fanfiction', the kidnapping could be part of a larger, more complex plot. Maybe it's a false kidnapping set up by an ally to test Ichigo's abilities. Or perhaps he's kidnapped by an otherworldly being for some unknown purpose. This could lead to a journey of self - discovery for Ichigo as he tries to figure out why he was targeted and how to get free.
In this fanfiction, Ichigo might be held in a secret location by Aizen. Aizen could be planning to use Ichigo for some dark experiment or to gain his power. Maybe he'll try to manipulate Ichigo's Hollow side for his own evil purposes.