according to the poorly written wikipedia article missing persons who are adults cannot be notified to their family. However I don't know if this applies if the person is clearly mentally deficient. If the hospital makes such a determination, hopefully his family can be notified.

That said, lol...I have a friend who is a police officer. He often gives us these stories of how his entire shift (and then some) gets ruined by some idiot who makes him drive all over town and then do paper work. Example:

Said friend gets a call to go to an apartment. Apparently some dudes had stolen some stuff. Said dudes were there, along with a woman. They were questioned and booked (they also appeared to be drug dealers). Anyway that's not the point. The point is that while leaving the girl decided to add "um...so the other night one of them stuck their penis in me and I sorta said they couldn't"

So now they had to drag her ass to a hospital for a rape kit to be done. Bye bye shift.