It took him quite some time to get used to the idea that his son was dating a guy he had arrested for murder once (not to mention after Stiles himself had accused him of it). A guy who was seven years older than his boy. A guy who he practically knew nothing about that wasn't written down in a file, way too big for a 24-year-old.
The Sheriff carried his doubts and worries around with him every day, for weeks. Every day when he stumbled upon worn out leather boots in the hallway - if Derek took the front door for once, instead of climbing through Stiles' window (weirdo); when he threw away yet another box of cereals that had been emptied within two days (because that Hale kid ate like he hadn't been fed for the last six years); when he had to explain the neighbors for the third time that the snazzy Camaro in front of their house wasn't a product of his late midlife crisis but in fact just the car of his son's boyfriend; every day he bundled up all his concerns and took them to work.
Sometimes during the day he would take them out again, let them run through his head and ask himself the same question over and over again. Was he making a mistake letting Derek Hale into his house? His life? His son's heart?
It never took much to make him believe he could see bad in Derek. At least bad for his son. He would witness several occasions that made him think he was watching a drama á la Tosca (or something) that was destined to end badly. Too many yelled insults, slammed doors and tears of anger would strengthen his doubts and hold him back from accepting him completely.
But it only took him one look on the couch that night to forget all his doubts and store them away for good. When he looked down on his son, curled up in Derek's arms, he didn't see a grown-up, stranger to him, possibly a bad influence or even a danger to his one and only son; his Stiles. He saw the sixteen-year-old that had been ripped off his family. Who had lost his life before it had even started; watched it burn down to ashes along with his family, his home.
Watching Derek's sleeping face free of its usual sternness, his pained expression, he saw the not-quite-so-grown up who had buried his sister and his uncle not long ago all by himself, staying behind as the only Hale left. He who had nothing and nobody in the world besides a sports car and his name, which was more important to him than one might think.
This and.. Stiles.
He saw the way Derek had wrapped his arms around Stiles, holding him protectively but also like his dear life depended on it. Like Stiles was the most precious thing he had ever possessed, the only thing that kept him from drowning. Something he wouldn’t – couldn’t – ever give up again.
That poor kid who had nobody left had found his peace in no other than the Sheriff's hyperactive, chaotic son who had spent half of his life searching for something as well. Something that had been taken from him years ago, when his mother had died, leaving him with a big black hole in his chest. The Sheriff knew it all too well, for the same emptiness was filling him. But other than Stiles, he knew he wouldn't find anything to fill it again. He had already been given his love, his happiness in this world and there was no way to get it back.
The Sheriff smiled down at them and picked up a blanket to cover them up. He could see Derek shift, instinctively tightening his arms around Stiles who smacked his lips once and snuggled up into Derek’s shirt.
Maybe this was a tragic love story.
Maybe it was destined to end badly. Maybe not.
But one thing he knew for sure.
This was not a mistake. This was the most right thing in the world.