IMO, this man had nothing to do with Ky's disappearance.
That said, I witnessed a neighbor who experienced a psychotic break. He was fine and dandy ... and then, one day, he was at my door, wanting access to my deck, to see if the "towers" were in view (TV transmission towers on Cougar Mountain, east of Seattle). I wasn't certain how to deal with him at the time. Tried to talk with him. It became apparent "something" was terribly wrong. I learned, later, he had -- that same day -- ripped his mailbox off the community mail stand. I also learned (by way of his "girlfriend" (caregiver) he had been given, around the same time, painkillers for muscle aches and medication for sight loss.
This was in the spring. All summer, his condition worsened. Neighbors (not me) called the police, reporting his "martial arts" movements and screaming threats directed toward cars and passing pedestrians. The police told him to stay in his backyard. He did.
But I could hear him. He argued and yelled at people who weren't there. He kicked my screen door (it was scary, but I also knew he considered me "part of the plan"). He ran away from his "girlfriend"/caregiver. I had her phone number. I called her when he climbed on his roof and yelled/argued with personalities seen only by his deranged brain. She talked him down.
What to do? As with many states, WA has a 72 hour limit on psych holds for involuntary commitments. This man spent 9 months yelling at non-existent (or least unseen) people, spiraling deeper into paranoid schizophrenia: He trashed his satellite dish, ripped all telephone lines out of his house, cut open the walls to get at the remaining "transmission lines."
He finally shook his "girlfriend"/caregiver so hard, he was arrested. She didn't want to see him in jail; neither did I; but he had finally proven a danger to someone else and could be -- psychiatrically -- treated without his permission. I wrote a letter to the court, explaining he needed treatment, not jail time. Treatment is, at long last, what he received.
To reiterate: IMO, pulling DAD into Ky's case is not only wrong, it's possibly harmful to DAD. The man has, IMO, paranoid schizophrenia. Its not beyond possibility he rode the wire with this condition and was able to maintain until he was given a drug cocktail for his injured shoulder.
Someone in this thread asked if there is such a thing as a psychotic break. Yes. There is. It can happen quickly. And most states would like to ignore the danger posed by such breaks until someone is either injured or killed.