In fanfics, all kinds of scenarios are possible. Just because it's written doesn't mean it adheres to the original canon. Maybe the author wanted to explore a unique relationship dynamic through this pregnancy plot. However, without reading it, it's hard to say more about it.
I don't know who Sam is without reading the 'kings fund sam's story'. Sam could be a patient, a researcher, a staff member or someone else related to the Kings Fund.
Sam could be just an ordinary guy who loves exploring the woods. He might be a nature enthusiast who spends his free time in the forest, and one day he just happens to come across Bella.
Sam Evans in 'sam evans first time fiction' is a mystery. He could be an aspiring writer who is making his first foray into fiction writing. Or he could be a fictional character in the story, with his own unique backstory and personality. We just need more information to be certain.
The plot could center around the emotional journey. Sam may experience a range of emotions from joy to fear. Danny could be there to comfort and encourage. They might also face difficulties such as financial concerns. For example, they'll need to think about buying baby stuff, finding a bigger place if needed. And as the pregnancy progresses, they'll have to start thinking about Dani's future, like education and what kind of life they want to provide for the child.
It could be related to some sort of power struggle. Suppose there's a power or ability that Sam has that Tucker wants, and he believes the only way to get it is by getting rid of Sam. Another possibility is that Tucker has been influenced by some dark force or entity that has compelled him to do this evil deed. This could add an element of the supernatural to the story and explain his otherwise out - of - character behavior.
It could lead to a lot of relationship changes. Maybe their friends and family in the fanfic world would have different reactions, either supportive or against it.
Dean is almost always going to be in these fanfictions when Sam is gagged. Their relationship is central to Supernatural. Rowena could also be a character. She might use her magic to either gag Sam for her own purposes or to help him if she has a change of heart. And Gabriel. He could turn up and use his trickster abilities to either put Sam in the gagged situation as a joke or to get him out of a more serious one.
Carly would probably be the first one to take care of Sam. They're best friends, after all. She'd bring her soup and make sure she has enough blankets.