This is quite easy to get if you know what you need to do! The game is very easy to get lost in, especially if you get bitten by a snake or break a bone. To put it simply, you need to hide with the kid in the first rocks you see (ignore the scary noises and just cross the river and hide in the first rocks you come to. Then when you have control of the adult, use your senses to find the kid. Once you have him, return to the settlement at the top of the waterfall.