I can understand how things can happen when you're still in the room or just in the next room, and you didn't hear - we got burgled one summer night, the bloke came in the bedroom window while I was in the shower and husband was in the very next room, doors open between. husband didn't hear a thing, neither did I. I came out of the bathroom, stopped to speak to husband as I walked past or I would have seen the guy's face. However, he heard me stop and speak so he was heading back out the window as I went into the room. I got a good look at the back of him. If he had stayed, he'd have got a good look at the FRONT of me, fresh from the shower.
I also know from past experience just how soundly teens can sleep!
If the dad is only 20, having a girlfriend who is 17 seems perfectly normal. Maybe not legal (depending on local laws) but hey, whoever said kids worry about what is legal when it comes to their relationships?
I do hope this child is found safe. It does sound like she is also capable of going off on her own. I used to be afraid of the dark, but when I woke up at night and it already WAS dark, or there was some light outside from moon, or street lights, I would sometimes get up and look out of the window, or sometimes quietly took myself outside. I knew how to unlock the door and would do it quietly, then let myself back in later and put the key back. I don't think my mother ever knew how much I wandered. There is a surprising amount of light even before false dawn.
Marg