Okay, you have to watch the video. This 18 year old boy hesitates for at least 2 minutes before grabbing Cash, he is really hesitating for awhile. He grabs the boy who was already asleep, not the one who returned to the bed at the beginning of the video. It appears to me that the 18 year old is communicating with someone possibly via earbud..... not communicating but listening to someone maybe. I am not sure. The way he hesitates is very revealing and it shows (to me) that this was someone else's idea and he was sent to do the job of snatching Cash.
Now, even more telling is when the 18 year old returns after daybreak. He is talking to someone - someone is there - someone who knows there is only one boy in the bed. (it's a toddler bed not a crib by the way). He at first says " he is sound asleep " then other things which I haven't interpreted yet. So there you have it. More than one person involved. This explains why nobody did anything to stop it.
Add that to the fact that dad's ex-girlfriend knew these boys had a mother; and mother says boys were missing since March. It adds up. Look at the video. You have to in order to understand. I will watch again and analyze to see what else he might have said. To me he is clearly talking to someone else.
Also, most painful part is when the twin comes back into the room and looks at the empty toddler bed. It's as if his heart knows, but his little 4 year old mind cannot comprehend, nor speak what his heart knows.