LF Stiles being done with the Hales
I remember the Hales were alive and Stiles had to meet with them because of a custom to see if he should join their pack. There was previously a series of misunderstandings, so no one in the pack liked Stiles. The misunderstandings started with Talia believing that Stiles had vandalized and sabotaged her car right before she went into labor endangering her child. She then crosses a line by ordering Peter to "interrogate" Stiles to get answers. Stiles gives a reason you suck speech to the Hales, pointing out how Talia forcing the sheriff to pay for repairs to her car, despite the lack of evidence, cost her the respect of the police who now consider any cases regarding action against the Hales a low priority. Stiles explicitly states that the person who hated the Hales enough to sneak onto their property, vandalize a car, and endanger Baby Hale is never going to be caught because the sheriff hates Talia and isn't looking for them.
Stiles is also part fox shifter, which means he can get pregnant and has already given birth to Talia's grandchild by the start of the fic. Derek recognized Stiles as his mate and claimed him before going off to college because he didn't want to risk Stiles getting with someone else while he was away. However, since no one knew about this, when Stiles tried to explain he was pregnant with Derek's child, it was assumed he was delusional. This resulted in him being involuntarily committed to Eichen House and heavily medicated until it became obvious that he was actually pregnant. So while Derek was planning to inform his family during the customary meet and greet that Stiles was his mate, Stiles was only there to get closure and had no intention of becoming Derek's mate officially.
There was a happy ending where Stiles did join the Hale pack for his child's sake and got back with Derek.