The beep was steady and constant, it provided reassurance that Stiles had come through the worst of his self inflicted injuries. Sherriff Stilinski couldn't blame Stiles for slitting his wrists, he'd been kept from his mate by circumstances that were beyond his control. Yes the Sherriff knew about werewolves, and he knew that Derek and Stiles were mates. He also knew that Stiles had been forced out of the Hale pack, by Scott and his misguided notion that he was protecting Stiles, by excluding him from wolf business. The Sherriff knew that the Argent girl wasn't Scott's mate and was trying to figure out how to make this apparent to Scott, before she got anymore involved in wolf business. She was a hunter, it was her birth-right and nothing could change that, not even her little high school crush on Scott. In fact the Sherriff only knew of one hunter, who was werewolf's mate and he had managed to suppress the mating instinct that, as a wolf's mate, existed with in him.
The Sherriff knew a great deal about werewolf's, packs, mates and wolf business in general. It was part of the reason why he hadn't inflicted a more severe punishment on Stiles, when he'd taken the prison transporter to eliminate the threat posed by the Whittemore boy. The Sherriff had been able to hear that Stiles was lying, that was a gift that any parent would kill for, he'd also been able to smell the truth on Stiles. He could smell the Hale pack, i.e. Derek on Stiles. He could smell the other wolves too, he could smell the Kanima although having never dealt with a Kanima before, he had no idea what exactly he was smelling. Yes the Sherriff was a werewolf and when Stiles woke up, it would be necessary to reveal the truth to Stiles. Sure he'd be upset that the Sherriff had withheld the truth from him for so long and he'd be devastated that he, himself, wasn't a werewolf. But he'd be relieved to know that if he recieved an Alpha bite, from the Sherriff or Derek, there was no danger of him dying.
Once the Sherriff revealed the truth to Stiles and by extension the Hale Pack, it would be necessary to educate them all on the history of the werewolves of Beacon Hills. It would also be necessary to eliminate the Argents, by eliminate he didn't necessarily mean kill. But the treaties the Argents had entered into with the Hale Pack where a band aid, an inadeuate band aid designed to benefit the Argent's. Restrictions on the bite, preventing a wolf from turning their mate. Derek obviously hadn't picked up on that one, maybe because he was trying to repress his mating instinct and the knowledge that Stiles was his mate. Beacon Hills had always been a peaceful community and the current supernatural mess, could be traced back to the Argents and their lack of respect for their own code. The Hale house fire, the death of Jackson Whittemore's birth parents and the massacre of the Cage Pack had all been orcastrated by the Argents and each of those events led directly to..
Peter Hale becoming an Alpha!
Jackson Whittemore becoming the Kanima!
The Arrival of the Alpha Pack!
Yes, the Argents knew how to destroy the Supernatural. But they did so without respect for the Supernatural and that had lead to chaos. Kate's lack of respect for the Supernatural resulted in Peter Hale's revenge, the Sherriff thought he deserved his revenge. Because the Sherriff although he knew the Argents where responsible for that fire, couldn't prove it and couldn't resort to a more Supernatural approach since he was trying to keep a low profile. Gerard's lack of respect for the Supernatural would have resulted in his death, if Scott hadn't been dosing him with Mountain Ash, for the bite to take both the Alpha and recipient of the bite have to be willing. But the eventual re-emergence of Gerard Argent was pretty low on the Sherriff's list of priorities, so was dealing with the rest of the Argent's. It was essential to eliminate the threat of the Alpha Pack before people got killed. But all of that could wait until Stiles was awake and aware of his heritage, safe and once again belonging to a wolf pack.